SMTP Component

Properties Methods Events Config Settings Errors

The SMTP Component is used to send internet mail using the SMTP protocol (the internet mail standard).

Syntax

nsoftware.IPWorksEDI.SMTP

Remarks

The SMTP Component supports both plaintext and Secure Sockets Layer/Transport Layer Security (SSL/TLS) connections (RFC 2487). When connecting over Secure Sockets Layer/Transport Layer Security (SSL/TLS) the SSLServerAuthentication event allows you to check the server identity and other security attributes. The SSLStatus event provides information about the SSL handshake. Additional SSL-related settings are also supported through the Config method.

The SMTP Component implements a standard SMTP client as specified in RFC 821. It has a simple plug-and-play interface. It contains a number of properties, such as SendTo, Subject, From, Cc, and BCc, that map directly to the internet mail message headers with the same name (RFC 822). The message text is set in MessageText. Messages are sent by calling the Send method.

The component supports message delivery to multiple recipients through the SendTo, Cc, and BCc properties. Simply specify the destination email addresses separated by commas.

The interface of the component is open-ended. New features, including MIME attachments, can be supported by using the OtherHeaders property.

A number of events provide feedback during the operation of the component. The Transfer event is fired during message delivery to show the number of bytes delivered. The PITrail event traces the commands that are sent to the server and the respective replies.

Property List

The following is the full list of the properties of the component with short descriptions. Click on the links for further details.


AllowExtensions	This property is a switch allowing the component to use ESMTP features (Extended SMTP).
AuthMechanism	This property is used when connecting to the mail server.
BCc	This property includes a comma-separated list of addresses for blind carbon copies (optional).
Cc	This property includes a comma-separated list of addresses for carbon copies (optional).
Connected	Whether the component is connected.
DeliveryNotificationTo	This property includes the email address to which to send a delivery notification.
Firewall	A set of properties related to firewall access.
From	This property includes the email address of the sender (required).
Idle	The current status of the component.
Importance	This property indicates the importance of the mail message (optional).
LastReply	This property indicates the last reply received from the server.
LocalHost	The name of the local host or user-assigned IP interface through which connections are initiated or accepted.
MailPort	This property includes the server port for SMTP (default 25).
MailServer	This property includes the name or address of a mail server (mail relay).
Message	This property provides a way to set the raw message content.
MessageDate	This property includes the date of the mail message (optional).
MessageHeaders	This property includes a collection of RFC 822-encoded headers of the message.
MessageHeadersString	This property includes the string representation of RFC 822-encoded headers of the message.
MessageId	This property includes the message identifier for the message.
MessageRecipients	This property includes the collection of recipients of the message.
MessageText	This property includes the full text of the message to send (without headers).
OtherHeaders	This property includes an RFC 822-compliant string consisting of extra headers.
Password	This property includes a password for logon to the MailServer .
Priority	This property includes the priority of the mail message (optional).
ReadReceiptTo	This property includes the email address to send a read-receipt to.
ReplyTo	This property includes a mail address to which to reply (optional).
ReturnPath	This property sets the Return-Path to be used for sending email.
SendTo	This property includes a comma-separated list of addresses for destinations (required).
Sensitivity	This property indicates the sensitivity of the mail message (optional).
SSLAcceptServerCert	Instructs the component to unconditionally accept the server certificate that matches the supplied certificate.
SSLCert	The certificate to be used during Secure Sockets Layer (SSL) negotiation.
SSLEnabled	This property indicates whether Transport Layer Security/Secure Sockets Layer (TLS/SSL) is enabled.
SSLProvider	The Secure Sockets Layer/Transport Layer Security (SSL/TLS) implementation to use.
SSLServerCert	The server certificate for the last established connection.
SSLStartMode	This property determines how the component starts the Secure Sockets Layer (SSL) negotiation.
Subject	This property includes the subject of the mail message (optional).
Timeout	The timeout for the component.
User	This property includes the user identifier needed to log in as in the MailServer .

Method List

The following is the full list of the methods of the component with short descriptions. Click on the links for further details.


Config	Sets or retrieves a configuration setting.
Connect	This method connects to the mail relay and sends the SMTP `HELO` command.
Disconnect	This method disconnects from the SMTP server.
DoEvents	This method processes events from the internal message queue.
Expand	This method asks the MailServer to expand a name or mailing list.
Interrupt	This method interrupts the current method.
ProcessQueue	This method sends the messages that previously have been queued into `QueueDir` .
Queue	This method queues the message into `QueueDir` .
Reset	This method will reset the component.
ResetHeaders	This method resets all the message headers to empty.
Send	This method sends the current message.
SendCommand	This method sends the exact command directly to the server.
SendToTerminalAndEmail	This method sends to terminal and email.
SendToTerminalOnly	This method sends to terminal only.
SendToTerminalOrEmail	This method sends to terminal or email.
SetMessageStream	This method sets the stream to be uploaded to the server as part of the message.
Verify	This method sends a verification request to the SMTP server.

Event List

The following is the full list of the events fired by the component with short descriptions. Click on the links for further details.


ConnectionStatus	Fired to indicate changes in the connection state.
EndTransfer	This event is fired when the message text completes transferring.
Error	Fired when information is available about errors during data delivery.
Expand	This event is fired for every email address returned by the server when the Expand method is called.
PITrail	This event traces the commands sent to the mail server, and the respective replies.
SSLServerAuthentication	Fired after the server presents its certificate to the client.
SSLStatus	Fired when secure connection progress messages are available.
StartTransfer	This event is fired when the message text starts transferring.
Transfer	This event is fired when the message text is transferred to MailServer .

Config Settings

The following is a list of config settings for the component with short descriptions. Click on the links for further details.


AllowEmptyTo	If set to True, then the SendTo property is not required.
AuthorizationIdentity	The value to use as the authorization identity when SASL authentication is used.
Charset	When set, the message headers will be encoded using the specified Charset.
FoldHeaders	Tells the component whether to fold the headers.
Hello	The argument for HELO (herald) command to the server (defaults to local host name).
KeepQueue	If set to True, queued files are not deleted after a successful send.
MaxHeaderLength	Maximum length for headers to avoid line folding (default 80).
MessageHeadersString	String representation of RFC822-encoded headers of the message.
MessageIdAlgorithm	Determines the algorithm used to hash the random MessageId.
OtherHeaders	An RFC 822 compliant string consisting of extra headers.
ReturnPath	Sets the Return-Path to be used for sending email.
SendRSET	Whether to send RSET command.
StopOnBccErrors	Instructs the component to stop sending the message if the server does not acknowledge any of the BCCs.
StopOnCcErrors	Instructs the component to stop sending the message if the server does not acknowledge any of the CCs.
StopOnToErrors	Instructs the component to stop sending the message if the server does not acknowledge any of the TOs.
TransferText	String representation of RFC822-encoded body of the message.
CloseStreamAfterTransfer	If true, the component will close the upload or download stream after the transfer.
ConnectionTimeout	Sets a separate timeout value for establishing a connection.
FirewallAutoDetect	Tells the component whether or not to automatically detect and use firewall system settings, if available.
FirewallHost	Name or IP address of firewall (optional).
FirewallListener	If true, the component binds to a SOCKS firewall as a server (TCPClient only).
FirewallPassword	Password to be used if authentication is to be used when connecting through the firewall.
FirewallPort	The TCP port for the FirewallHost;.
FirewallType	Determines the type of firewall to connect through.
FirewallUser	A user name if authentication is to be used connecting through a firewall.
KeepAliveInterval	The retry interval, in milliseconds, to be used when a TCP keep-alive packet is sent and no response is received.
KeepAliveTime	The inactivity time in milliseconds before a TCP keep-alive packet is sent.
Linger	When set to True, connections are terminated gracefully.
LingerTime	Time in seconds to have the connection linger.
LocalHost	The name of the local host through which connections are initiated or accepted.
LocalPort	The port in the local host where the component binds.
MaxLineLength	The maximum amount of data to accumulate when no EOL is found.
MaxTransferRate	The transfer rate limit in bytes per second.
ProxyExceptionsList	A semicolon separated list of hosts and IPs to bypass when using a proxy.
TCPKeepAlive	Determines whether or not the keep alive socket option is enabled.
TcpNoDelay	Whether or not to delay when sending packets.
UseIPv6	Whether to use IPv6.
UseNTLMv2	Whether to use NTLM V2.
CACertFilePaths	The paths to CA certificate files when using Mono on Unix/Linux.
LogSSLPackets	Controls whether SSL packets are logged when using the internal security API.
ReuseSSLSession	Determines if the SSL session is reused.
SSLCACerts	A newline separated list of CA certificates to be included when performing an SSL handshake.
SSLCheckCRL	Whether to check the Certificate Revocation List for the server certificate.
SSLCheckOCSP	Whether to use OCSP to check the status of the server certificate.
SSLCipherStrength	The minimum cipher strength used for bulk encryption.
SSLClientCACerts	A newline separated list of CA certificates to use during SSL client certificate validation.
SSLEnabledCipherSuites	The cipher suite to be used in an SSL negotiation.
SSLEnabledProtocols	Used to enable/disable the supported security protocols.
SSLEnableRenegotiation	Whether the renegotiation_info SSL extension is supported.
SSLIncludeCertChain	Whether the entire certificate chain is included in the SSLServerAuthentication event.
SSLKeyLogFile	The location of a file where per-session secrets are written for debugging purposes.
SSLNegotiatedCipher	Returns the negotiated cipher suite.
SSLNegotiatedCipherStrength	Returns the negotiated cipher suite strength.
SSLNegotiatedCipherSuite	Returns the negotiated cipher suite.
SSLNegotiatedKeyExchange	Returns the negotiated key exchange algorithm.
SSLNegotiatedKeyExchangeStrength	Returns the negotiated key exchange algorithm strength.
SSLNegotiatedVersion	Returns the negotiated protocol version.
SSLSecurityFlags	Flags that control certificate verification.
SSLServerCACerts	A newline separated list of CA certificates to use during SSL server certificate validation.
TLS12SignatureAlgorithms	Defines the allowed TLS 1.2 signature algorithms when SSLProvider is set to Internal.
TLS12SupportedGroups	The supported groups for ECC.
TLS13KeyShareGroups	The groups for which to pregenerate key shares.
TLS13SignatureAlgorithms	The allowed certificate signature algorithms.
TLS13SupportedGroups	The supported groups for (EC)DHE key exchange.
AbsoluteTimeout	Determines whether timeouts are inactivity timeouts or absolute timeouts.
FirewallData	Used to send extra data to the firewall.
InBufferSize	The size in bytes of the incoming queue of the socket.
OutBufferSize	The size in bytes of the outgoing queue of the socket.
BuildInfo	Information about the product's build.
GUIAvailable	Whether or not a message loop is available for processing events.
LicenseInfo	Information about the current license.
MaskSensitiveData	Whether sensitive data is masked in log messages.
UseFIPSCompliantAPI	Tells the component whether or not to use FIPS certified APIs.
UseInternalSecurityAPI	Whether or not to use the system security libraries or an internal implementation.

AllowExtensions Property (SMTP Component)

This property is a switch allowing the component to use ESMTP features (Extended SMTP).

public bool AllowExtensions { get; set; }

Public Property AllowExtensions As Boolean

Default Value

True

Remarks

This property is a switch allowing the component to use ESMTP features (Extended SMTP). If this property is True, the component will first send the EHLO greeting (Extended Hello) to the server and, if that fails, the standard HELO command will be sent.

This property is True by default but may be disabled if it is known in advance that the MailServer does not support SMTP extensions.

This property is not available at design time.

AuthMechanism Property (SMTP Component)

This property is used when connecting to the mail server.

Syntax

C#
VB.NET

public SMTPAuthMechanisms AuthMechanism { get; set; }

enum SMTPAuthMechanisms {
  amUserPassword,
  amCRAMMD5,
  amNTLM,
  amAPOP,
  amSASLPlain,
  amSASLDigestMD5,
  amKerberos,
  amXOAUTH2
}

Public Property AuthMechanism As SmtpAuthMechanisms

Enum SMTPAuthMechanisms
  amUserPassword
  amCRAMMD5
  amNTLM
  amAPOP
  amSASLPlain
  amSASLDigestMD5
  amKerberos
  amXOAUTH2
End Enum

Default Value

Remarks

This is the authentication mechanism property to be used when connecting to the mail server.

By default, this property is amUserPassword (0), and if the User and Password properties are set, the AUTH command is sent to the server for authentication. If this property is set to amCRAMMD5 (1), CRAM-MD5 authentication is used instead.

If this property is set to amNTLM (2), NTLM authentication will be used.

If this property is set to amKerberos (6), Kerberos authentication will be used.

Note: This functionality is available only in Windows.

When set to amXOAUTH2 (7), set User to the username and AuthorizationIdentity to the OAuth token. See AuthorizationIdentity for details.

BCc Property (SMTP Component)

This property includes a comma-separated list of addresses for blind carbon copies (optional).

Syntax

C#
VB.NET

public string BCc { get; set; }

Public Property BCc As String

Default Value

Remarks

This property specifies a comma-separated list of destinations for blind carbon copies of the mail message. A copy of the message is sent to each destination. Because no BCc SMTP header is created containing the destination addresses, individual recipients never see the list of the other recipients.

The component will return an error if the MailServer returns an error code about any email address specified in SendTo or Cc but it will fire an Error event only if the same thing happens with an email address specified in this property.

If the resulting header is longer than MaxHeaderLength, then it is folded according to RFC 822 specifications.

Note: You must clear the MessageRecipients collection before setting this property to remove previous recipients.

Cc Property (SMTP Component)

This property includes a comma-separated list of addresses for carbon copies (optional).

Syntax

C#
VB.NET

public string Cc { get; set; }

Public Property Cc As String

Default Value

Remarks

This property specifies a comma-separated list of destinations for carbon copies of the mail message. A copy of the message is sent to each destination, and a Cc SMTP header is created containing the destination addresses. This header is sent to every recipient of the message. If you don't want to copy this information to every recipient, then use blind carbon copies instead (see the description of the BCc).

If the resulting header is longer than MaxHeaderLength, then it is folded according to RFC 822 specifications.

Note: You must clear the MessageRecipients collection before setting this property to remove previous recipients.

Connected Property (SMTP Component)

Whether the component is connected.

Syntax

C#
VB.NET

public bool Connected { get; }

Public ReadOnly Property Connected As Boolean

Default Value

False

Remarks

This property is used to determine whether or not the component is connected to the remote host. Use the Connect and Disconnect methods to manage the connection.

This property is read-only and not available at design time.

DeliveryNotificationTo Property (SMTP Component)

This property includes the email address to which to send a delivery notification.

Syntax

C#
VB.NET

public string DeliveryNotificationTo { get; set; }

Public Property DeliveryNotificationTo As String

Default Value

Remarks

This property contains the email address to send to which to send a delivery notification. When set, a Return-Receipt-To header is added to the message. This property should be set to an email address that can receive the delivery notification.

Firewall Property (SMTP Component)

A set of properties related to firewall access.

Syntax

C#
VB.NET

public Firewall Firewall { get; set; }

Public Property Firewall As Firewall

Remarks

This is a Firewall-type property, which contains fields describing the firewall through which the component will attempt to connect.

Please refer to the Firewall type for a complete list of fields.

From Property (SMTP Component)

This property includes the email address of the sender (required).

Syntax

C#
VB.NET

public string From { get; set; }

Public Property From As String

Default Value

Remarks

This property is used to create a From SMTP header. This header identifies the sender of the message. A valid email address is required. Examples of valid addresses are as follows: "Friendly Name" <address@company.com> or address@company.com

If the resulting header is longer than MaxHeaderLength, then it is folded according to RFC 822 specifications.

Idle Property (SMTP Component)

The current status of the component.

Syntax

C#
VB.NET

public bool Idle { get; }

Public ReadOnly Property Idle As Boolean

Default Value

True

Remarks

This property will be False if the component is currently busy (communicating or waiting for an answer), and True at all other times.

This property is read-only.

Importance Property (SMTP Component)

This property indicates the importance of the mail message (optional).

Syntax

C#
VB.NET

public SMTPImportances Importance { get; set; }

enum SMTPImportances {
  miUnspecified,
  miHigh,
  miNormal,
  miLow
}

Public Property Importance As SmtpImportances

Enum SMTPImportances
  miUnspecified
  miHigh
  miNormal
  miLow
End Enum

Default Value

Remarks

This property indicates the importance of the mail message (optional). When set, an Importance header will be added to the message.

Importance is an indication to the recipient(s) about the level of importance of the message. The possible values are Unspecified (0), High (1), Normal (2), and Low (3).

LastReply Property (SMTP Component)

This property indicates the last reply received from the server.

Syntax

C#
VB.NET

public string LastReply { get; }

Public ReadOnly Property LastReply As String

Default Value

Remarks

This property indicates the last reply received from the server. It can be used for informational purposes. The same information and more also can be retrieved through the PITrail event.

This property is read-only.

LocalHost Property (SMTP Component)

The name of the local host or user-assigned IP interface through which connections are initiated or accepted.

Syntax

C#
VB.NET

public string LocalHost { get; set; }

Public Property LocalHost As String

Default Value

Remarks

This property contains the name of the local host as obtained by the gethostname() system call, or if the user has assigned an IP address, the value of that address.

In multihomed hosts (machines with more than one IP interface) setting LocalHost to the IP address of an interface will make the component initiate connections (or accept in the case of server components) only through that interface. It is recommended to provide an IP address rather than a hostname when setting this property to ensure the desired interface is used.

If the component is connected, the LocalHost property shows the IP address of the interface through which the connection is made in internet dotted format (aaa.bbb.ccc.ddd). In most cases, this is the address of the local host, except for multihomed hosts (machines with more than one IP interface).

Note: LocalHost is not persistent. You must always set it in code, and never in the property window.

MailPort Property (SMTP Component)

This property includes the server port for SMTP (default 25).

Syntax

C#
VB.NET

public int MailPort { get; set; }

Public Property MailPort As Integer

Default Value

Remarks

This property contains the server port for SMTP (default 25). A valid port number (a value between 1 and 65535) is required for the connection to take place. The property must be set before a connection is attempted and cannot be changed once a connection is established. Any attempt to change this property while connected will fail with an error.

For an implicit Secure Sockets Layer (SSL), use port 465 (please refer to the SSLStartMode property for more information).

This property is not available at design time.

MailServer Property (SMTP Component)

This property includes the name or address of a mail server (mail relay).

Syntax

C#
VB.NET

public string MailServer { get; set; }

Public Property MailServer As String

Default Value

Remarks

This property specifies the IP address (IP number in dotted internet format) or domain name for a mail relay through which messages will be routed. It is set before a connection is attempted and cannot be changed once a connection is in progress.

The current version of the component does not provide a default value for the mail relay. You must provide a host name yourself. Generally, any internet host with an SMTP server will suffice (e.g., a UNIX host), but it is preferable to select a MailServer that is close to the machine sending mail.

If this property is set to a domain name, a DNS request is initiated. Upon successful termination of the request, this property is set to the corresponding address. If the search is not successful, an error is returned.

If the component is configured to use a SOCKS firewall, the value assigned to this property may be preceded with an "*". If this is the case, the host name is passed to the firewall unresolved and the firewall performs the DNS resolution.

Message Property (SMTP Component)

This property provides a way to set the raw message content.

Syntax

C#
VB.NET

public string Message { get; set; }
public byte[] MessageB { get; set; }

Public Property Message As String
Public Property MessageB As Byte()

Default Value

Remarks

This property may be set instead of MessageText. This value will not be modified in any way by the component and will be sent as is. Use caution when setting this value as all encoding must be done before supplying the value to the component.

This property is not available at design time.

MessageDate Property (SMTP Component)

This property includes the date of the mail message (optional).

Syntax

C#
VB.NET

public string MessageDate { get; set; }

Public Property MessageDate As String

Default Value

"*"

Remarks

If this property contains a nonempty string, then a Date SMTP header is created and attached to the message. If it is an empty string, then the date information is added by the mail relay(s) the message goes through.

Special case: If this property is set to the special value "*", a Date SMTP header reflecting the current date and time is generated when MessageHeaders is computed and the message is sent. This is the default behavior of the component

RFC 822 contains detailed date format specifications. An example of a valid date is "Fri, 1 Mar 96 21:24:52 EST".

This property is not available at design time.

MessageHeaders Property (SMTP Component)

This property includes a collection of RFC 822-encoded headers of the message.

Syntax

C#
VB.NET

public HeaderList MessageHeaders { get; }

Public ReadOnly Property MessageHeaders As HeaderList

Remarks

This property holds the full headers of the message in RFC 822 format.

This property is read-only and not available at design time.

Please refer to the Header type for a complete list of fields.

MessageHeadersString Property (SMTP Component)

This property includes the string representation of RFC 822-encoded headers of the message.

Syntax

C#
VB.NET

public string MessageHeadersString { get; }

Public ReadOnly Property MessageHeadersString As String

Default Value

Remarks

This property holds the full headers of the message in RFC 822 format.

This property is read-only.

MessageId Property (SMTP Component)

This property includes the message identifier for the message.

Syntax

C#
VB.NET

public string MessageId { get; set; }

Public Property MessageId As String

Default Value

"*"

Remarks

This property contains the message identifier for the message. When set, the value of MessageId is used as the Message-Id header value of the message. A special value of "*" will automatically generate a random unique identifier for the message.

This property is not available at design time.

MessageRecipients Property (SMTP Component)

This property includes the collection of recipients of the message.

Syntax

C#
VB.NET

public MessageRecipientList MessageRecipients { get; }

Public Property MessageRecipients As MessageRecipientList

Remarks

This property contains a collection that describes to whom the message is being sent. You may include all recipients in this property, even Cc's and BCc's, which are specified by the type field.

This collection is indexed from 0 to count -1.

Please refer to the MessageRecipient type for a complete list of fields.

MessageText Property (SMTP Component)

This property includes the full text of the message to send (without headers).

Syntax

C#
VB.NET

public string MessageText { get; set; }

Public Property MessageText As String

Default Value

Remarks

This property contains the full text of the message.

The text contained in this property should be a collection of lines with lengths less than or equal to 80 bytes separated by CRLF ("\r\n") . The text in the message lines must contain 7-bit characters so that the message can successfully pass through the multitude of mail systems on the Internet.

The component automatically escapes lines that start with a "." by adding another as specified in RFC 821. The message text is unescaped by the receiving agent, so the process is fully transparent.

OtherHeaders Property (SMTP Component)

This property includes an RFC 822-compliant string consisting of extra headers.

Syntax

C#
VB.NET

public string OtherHeaders { get; set; }

Public Property OtherHeaders As String

Default Value

Remarks

This property contains a string of headers to be appended to the message headers created from other properties like SendTo, Subject, and so on.

The headers must be of the format "header: value" as specified in RFC 822. Header lines should be separated by CRLF ("\r\n") .

Use this property with caution. If this property contains invalid headers, message delivery might not be successful.

This property is useful for extending the functionality of the component. A good example is delivery of MIME-encoded messages.

Special case: If this property starts with an empty line (CRLF), then the value of this property is used instead of the normally computed message headers.

Example. Sending an Email with an Additional Header:

component.MailServer = "MyServer"; component.From = "me@server.com"; component.SendTo = "recipient@server.com"; component.Subject = "My Subject"; component.MessageText = "This is the message body."; component.OtherHeaders = "HeaderName: HeaderValue"; component.Send();

This property is not available at design time.

Password Property (SMTP Component)

This property includes a password for logon to the MailServer .

Syntax

C#
VB.NET

public string Password { get; set; }

Public Property Password As String

Default Value

Remarks

If this property is set to a nonempty string, then when connecting to the MailServer an AUTH or CRAM-MD5 (depending on the value of AuthMechanism) command is sent to provide authentication information for the user.

This property is not available at design time.

Priority Property (SMTP Component)

This property includes the priority of the mail message (optional).

Syntax

C#
VB.NET

public SMTPPriorities Priority { get; set; }

enum SMTPPriorities {
  epUnspecified,
  epNormal,
  epUrgent,
  epNonUrgent
}

Public Property Priority As SmtpPriorities

Enum SMTPPriorities
  epUnspecified
  epNormal
  epUrgent
  epNonUrgent
End Enum

Default Value

Remarks

When this property is set, a priority header will be added to the message. Priority is an indication about the delivery priority of the message. The possible values are epNormal, epUrgent, and epNonUrgent.

ReadReceiptTo Property (SMTP Component)

This property includes the email address to send a read-receipt to.

Syntax

C#
VB.NET

public string ReadReceiptTo { get; set; }

Public Property ReadReceiptTo As String

Default Value

Remarks

When this property is set, a Disposition-Notification-To header is added to the message. This property should be set to an email address that should receive the read-receipt.

ReplyTo Property (SMTP Component)

This property includes a mail address to which to reply (optional).

Syntax

C#
VB.NET

public string ReplyTo { get; set; }

Public Property ReplyTo As String

Default Value

Remarks

If this property contains a nonempty string, a Reply-To SMTP header is created for the message. This header shows the address to use for replies, which is useful if this address is different from the one in From.

If the resulting header is longer than MaxHeaderLength, then it is folded according to RFC 822 specifications.

ReturnPath Property (SMTP Component)

This property sets the Return-Path to be used for sending email.

Syntax

C#
VB.NET

public string ReturnPath { get; set; }

Public Property ReturnPath As String

Default Value

Remarks

Setting this property sets the Return-Path to be used for sending email. If this is not set, the value in the From property is used.

SendTo Property (SMTP Component)

This property includes a comma-separated list of addresses for destinations (required).

Syntax

C#
VB.NET

public string SendTo { get; set; }

Public Property SendTo As String

Default Value

Remarks

This property specifies a comma-separated list of destinations for the mail message. A copy of the message is sent to each of them, and a To SMTP header is created containing the destination addresses.

Examples of valid addresses are as follows: "Friendly Name" <address@company.com> or address@company.com

The component will fail if the MailServer returns an error code about any email address specified in SendTo or Cc but it will silently ignore the error if the same thing happens with an email address specified in BCc.

If the resulting header is longer than MaxHeaderLength, then it is folded according to RFC 822 specifications.

Note: You must clear the MessageRecipients collection before setting this property to remove previous recipients.

Sensitivity Property (SMTP Component)

This property indicates the sensitivity of the mail message (optional).

Syntax

C#
VB.NET

public SMTPSensitivities Sensitivity { get; set; }

enum SMTPSensitivities {
  esUnspecified,
  esPersonal,
  esPrivate,
  esCompanyConfidential
}

Public Property Sensitivity As SmtpSensitivities

Enum SMTPSensitivities
  esUnspecified
  esPersonal
  esPrivate
  esCompanyConfidential
End Enum

Default Value

Remarks

This property provides an indication of how sensitive it is to disclose the message to people other than the recipients of the message. When set, a Sensitivity header will added to the message. Possible values are as follows: esPersonal (1), esPrivate (2), and esCompanyConfidential (3).

SSLAcceptServerCert Property (SMTP Component)

Instructs the component to unconditionally accept the server certificate that matches the supplied certificate.

Syntax

C#
VB.NET

public Certificate SSLAcceptServerCert { get; set; }

Public Property SSLAcceptServerCert As Certificate

Remarks

If it finds any issues with the certificate presented by the server, the component will normally terminate the connection with an error.

You may override this behavior by supplying a value for SSLAcceptServerCert. If the certificate supplied in SSLAcceptServerCert is the same as the certificate presented by the server, then the server certificate is accepted unconditionally, and the connection will continue normally.

Note: This functionality is provided only for cases in which you otherwise know that you are communicating with the right server. If used improperly, this property may create a security breach. Use it at your own risk.

Please refer to the Certificate type for a complete list of fields.

SSLCert Property (SMTP Component)

The certificate to be used during Secure Sockets Layer (SSL) negotiation.

Syntax

C#
VB.NET

public Certificate SSLCert { get; set; }

Public Property SSLCert As Certificate

Remarks

This property includes the digital certificate that the component will use during SSL negotiation. Set this property to a valid certificate before starting SSL negotiation. To set a certificate, you may set the Encoded field to the encoded certificate. To select a certificate, use the store and subject fields.

Please refer to the Certificate type for a complete list of fields.

SSLEnabled Property (SMTP Component)

This property indicates whether Transport Layer Security/Secure Sockets Layer (TLS/SSL) is enabled.

Syntax

C#
VB.NET

public bool SSLEnabled { get; set; }

Public Property SSLEnabled As Boolean

Default Value

False

Remarks

This property specifies whether TLS/SSL is enabled in the component. When False (default), the component operates in plaintext mode. When True, TLS/SSL is enabled.

TLS/SSL may also be enabled by setting SSLStartMode. Setting SSLStartMode will automatically update this property value.

This property is not available at design time.

SSLProvider Property (SMTP Component)

The Secure Sockets Layer/Transport Layer Security (SSL/TLS) implementation to use.

Syntax

C#
VB.NET

public SMTPSSLProviders SSLProvider { get; set; }

enum SMTPSSLProviders {
  sslpAutomatic,
  sslpPlatform,
  sslpInternal
}

Public Property SSLProvider As SmtpSSLProviders

Enum SMTPSSLProviders
  sslpAutomatic
  sslpPlatform
  sslpInternal
End Enum

Default Value

Remarks

This property specifies the SSL/TLS implementation to use. In most cases the default value of 0 (Automatic) is recommended and should not be changed. When set to 0 (Automatic), the component will select whether to use the platform implementation or the internal implementation depending on the operating system as well as the TLS version being used.

Possible values are as follows:


0 (sslpAutomatic - default)	Automatically selects the appropriate implementation.
1 (sslpPlatform)	Uses the platform/system implementation.
2 (sslpInternal)	Uses the internal implementation.

Additional Notes

In most cases using the default value (Automatic) is recommended. The component will select a provider depending on the current platform.

When Automatic is selected, on Windows, the component will use the platform implementation. On Linux/macOS, the component will use the internal implementation. When TLS 1.3 is enabled via SSLEnabledProtocols, the internal implementation is used on all platforms.

The .NET Standard library will always use the internal implementation on all platforms.

SSLServerCert Property (SMTP Component)

The server certificate for the last established connection.

Syntax

C#
VB.NET

public Certificate SSLServerCert { get; }

Public ReadOnly Property SSLServerCert As Certificate

Remarks

This property contains the server certificate for the last established connection.

SSLServerCert is reset every time a new connection is attempted.

This property is read-only.

Please refer to the Certificate type for a complete list of fields.

SSLStartMode Property (SMTP Component)

This property determines how the component starts the Secure Sockets Layer (SSL) negotiation.

Syntax

C#
VB.NET

public SMTPSSLStartModes SSLStartMode { get; set; }

enum SMTPSSLStartModes {
  sslAutomatic,
  sslImplicit,
  sslExplicit,
  sslNone
}

Public Property SSLStartMode As SmtpSSLStartModes

Enum SMTPSSLStartModes
  sslAutomatic
  sslImplicit
  sslExplicit
  sslNone
End Enum

Default Value

Remarks

The SSLStartMode property may have one of the following values:


0 (sslAutomatic)	If the remote port is set to the standard plaintext port of the protocol (where applicable), the component will behave the same as if SSLStartMode is set to sslExplicit. In all other cases, SSL negotiation will be implicit (sslImplicit).
1 (sslImplicit)	The SSL negotiation will start immediately after the connection is established.
2 (sslExplicit)	The component will first connect in plaintext, and then will explicitly start SSL negotiation through a protocol command such as STARTTLS.
3 (sslNone - default)	No SSL negotiation; no SSL security. All communication will be in plaintext mode.

Subject Property (SMTP Component)

This property includes the subject of the mail message (optional).

Syntax

C#
VB.NET

public string Subject { get; set; }

Public Property Subject As String

Default Value

Remarks

The string in this property is sent with a Subject SMTP header to the mail recipient.

If the resulting header is longer than MaxHeaderLength, then it is folded according to RFC 822 specifications.

Timeout Property (SMTP Component)

The timeout for the component.

Syntax

C#
VB.NET

public int Timeout { get; set; }

Public Property Timeout As Integer

Default Value

Remarks

If the Timeout property is set to 0, all operations will run uninterrupted until successful completion or an error condition is encountered.

If Timeout is set to a positive value, the component will wait for the operation to complete before returning control.

The component will use DoEvents to enter an efficient wait loop during any potential waiting period, making sure that all system events are processed immediately as they arrive. This ensures that the host application does not freeze and remains responsive.

If Timeout expires, and the operation is not yet complete, the component throws an exception.

Note: By default, all timeouts are inactivity timeouts, that is, the timeout period is extended by Timeout seconds when any amount of data is successfully sent or received.

The default value for the Timeout property is 60 seconds.

User Property (SMTP Component)

This property includes the user identifier needed to log in as in the MailServer .

Syntax

C#
VB.NET

public string User { get; set; }

Public Property User As String

Default Value

Remarks

If this property is set to a nonempty string, then when connecting to the MailServer an AUTH or CRAM-MD5 (depending on the value of AuthMechanism) command is sent to provide authentication information for the user.

This property is not available at design time.

Config Method (SMTP Component)

Sets or retrieves a configuration setting.

Syntax

C#
VB.NET

public string Config(string configurationString);

Async Version
public async Task<string> Config(string configurationString);
public async Task<string> Config(string configurationString, CancellationToken cancellationToken);

Public Function Config(ByVal ConfigurationString As String) As String

Async Version
Public Function Config(ByVal ConfigurationString As String) As Task(Of String)
Public Function Config(ByVal ConfigurationString As String, cancellationToken As CancellationToken) As Task(Of String)

Remarks

Config is a generic method available in every component. It is used to set and retrieve configuration settings for the component.

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the component, access to these internal properties is provided through the Config method.

To set a configuration setting named PROPERTY, you must call Config("PROPERTY=VALUE"), where VALUE is the value of the setting expressed as a string. For boolean values, use the strings "True", "False", "0", "1", "Yes", or "No" (case does not matter).

To read (query) the value of a configuration setting, you must call Config("PROPERTY"). The value will be returned as a string.

Connect Method (SMTP Component)

This method connects to the mail relay and sends the SMTP HELO command.

Syntax

C#
VB.NET

public void Connect();

Async Version
public async Task Connect();
public async Task Connect(CancellationToken cancellationToken);

Public Sub Connect()

Async Version
Public Sub Connect() As Task
Public Sub Connect(cancellationToken As CancellationToken) As Task

Remarks

This method connects to the mail relay and sends the SMTP HELO command, thus preparing to send messages. Any number of messages can later be sent using the Send method.

Example. Connecting and Sending an Email:

control.MailServer = "MyServer" control.From = "me@server.com" control.SendTo = "recipient@server.com" control.Subject = "My Subject" control.MessageText = "This is the message body" control.Connect() control.Send() control.Disconnect()

Disconnect Method (SMTP Component)

This method disconnects from the SMTP server.

Syntax

C#
VB.NET

public void Disconnect();

Async Version
public async Task Disconnect();
public async Task Disconnect(CancellationToken cancellationToken);

Public Sub Disconnect()

Async Version
Public Sub Disconnect() As Task
Public Sub Disconnect(cancellationToken As CancellationToken) As Task

Remarks

This method disconnects from the mail relay.

DoEvents Method (SMTP Component)

This method processes events from the internal message queue.

Syntax

C#
VB.NET

public void DoEvents();

Async Version
public async Task DoEvents();
public async Task DoEvents(CancellationToken cancellationToken);

Public Sub DoEvents()

Async Version
Public Sub DoEvents() As Task
Public Sub DoEvents(cancellationToken As CancellationToken) As Task

Remarks

When DoEvents is called, the component processes any available events. If no events are available, it waits for a preset period of time, and then returns.

Expand Method (SMTP Component)

This method asks the MailServer to expand a name or mailing list.

Syntax

C#
VB.NET

public void Expand(string emailAddress);

Async Version
public async Task Expand(string emailAddress);
public async Task Expand(string emailAddress, CancellationToken cancellationToken);

Public Sub Expand(ByVal EmailAddress As String)

Async Version
Public Sub Expand(ByVal EmailAddress As String) As Task
Public Sub Expand(ByVal EmailAddress As String, cancellationToken As CancellationToken) As Task

Remarks

This method asks the MailServer to expand a name or mailing list. The resulting response is provided in one or more Expand events (one for each address). The component will try to connect to the mail relay if it is not already connected.

Interrupt Method (SMTP Component)

This method interrupts the current method.

Syntax

C#
VB.NET

public void Interrupt();

Async Version
public async Task Interrupt();
public async Task Interrupt(CancellationToken cancellationToken);

Public Sub Interrupt()

Async Version
Public Sub Interrupt() As Task
Public Sub Interrupt(cancellationToken As CancellationToken) As Task

Remarks

If there is no method in progress, Interrupt simply returns, doing nothing.

ProcessQueue Method (SMTP Component)

This method sends the messages that previously have been queued into QueueDir .

Syntax

C#
VB.NET

public void ProcessQueue(string queueDir);

Async Version
public async Task ProcessQueue(string queueDir);
public async Task ProcessQueue(string queueDir, CancellationToken cancellationToken);

Public Sub ProcessQueue(ByVal QueueDir As String)

Async Version
Public Sub ProcessQueue(ByVal QueueDir As String) As Task
Public Sub ProcessQueue(ByVal QueueDir As String, cancellationToken As CancellationToken) As Task

Remarks

This method sends the messages that previously have been queued into QueueDir. The PITrail event shows the interaction with the server as messages are processed.

This method looks in the directory for files with the extension ".queued" and starts processing them.

When processing starts, the file extension is changed to ".sending". If an error happens at this stage, the sending process is aborted, and the file extension is changed to ".failed".

If the file is successfully sent, the file is normally deleted, unless the KeepQueue configuration setting is set to True, in which case the file extension is instead changed to ".sent" and the queue file is not deleted.

Queue Method (SMTP Component)

This method queues the message into QueueDir .

Syntax

C#
VB.NET

public string Queue(string queueDir);

Async Version
public async Task<string> Queue(string queueDir);
public async Task<string> Queue(string queueDir, CancellationToken cancellationToken);

Public Function Queue(ByVal QueueDir As String) As String

Async Version
Public Function Queue(ByVal QueueDir As String) As Task(Of String)
Public Function Queue(ByVal QueueDir As String, cancellationToken As CancellationToken) As Task(Of String)

Remarks

This method queues the message into QueueDir. The message is queued into a unique file into the directory QueueDir for future processing.

QueueDir must already exist, or an error will be generated. Alternatively, QueueDir may be set to "*" to return the result as a string instead of writing it to a file.

This method returns the name of the unique queue file created in QueueDir. The file extension is ".queued".

Please refer to the ProcessQueue method for more information on email queue processing.

Reset Method (SMTP Component)

This method will reset the component.

Syntax

C#
VB.NET

public void Reset();

Async Version
public async Task Reset();
public async Task Reset(CancellationToken cancellationToken);

Public Sub Reset()

Async Version
Public Sub Reset() As Task
Public Sub Reset(cancellationToken As CancellationToken) As Task

Remarks

This method will reset the component's properties to their default values.

ResetHeaders Method (SMTP Component)

This method resets all the message headers to empty.

Syntax

C#
VB.NET

public void ResetHeaders();

Async Version
public async Task ResetHeaders();
public async Task ResetHeaders(CancellationToken cancellationToken);

Public Sub ResetHeaders()

Async Version
Public Sub ResetHeaders() As Task
Public Sub ResetHeaders(cancellationToken As CancellationToken) As Task

Remarks

This method resets all the message headers to "" (empty string). Use this method before creating a new message, so that headers from the previous message are not carried over to the next one.

Send Method (SMTP Component)

This method sends the current message.

Syntax

C#
VB.NET

public void Send();

Async Version
public async Task Send();
public async Task Send(CancellationToken cancellationToken);

Public Sub Send()

Async Version
Public Sub Send() As Task
Public Sub Send(cancellationToken As CancellationToken) As Task

Remarks

This method sends the current message. If the component is not connected to the mail relay, a connection is created, the message is sent, and then the connection is closed unless an error occurs.

If the component is already connected (by use of the Connect method), the connection will remain open after the message is sent. To disconnect, call the Disconnect method.

Example. Send an Email:

SMTPControl.MailServer = "MyServer" SMTPControl.From = "me@server.com" SMTPControl.SendTo = "recipient@server.com" SMTPControl.Subject = "My Subject" SMTPControl.MessageText = "This is the message body" SMTPControl.Send()

SendCommand Method (SMTP Component)

This method sends the exact command directly to the server.

Syntax

C#
VB.NET

public void SendCommand(string command);

Async Version
public async Task SendCommand(string command);
public async Task SendCommand(string command, CancellationToken cancellationToken);

Public Sub SendCommand(ByVal Command As String)

Async Version
Public Sub SendCommand(ByVal Command As String) As Task
Public Sub SendCommand(ByVal Command As String, cancellationToken As CancellationToken) As Task

Remarks

This method sends the command specified by Command to the server exactly as it is provided. Use this method to send additional or custom commands directly to the server.

After calling this method, check the LastReply property or monitor the PITrail event to obtain the server's response.

SendToTerminalAndEmail Method (SMTP Component)

This method sends to terminal and email.

Syntax

C#
VB.NET

public void SendToTerminalAndEmail();

Async Version
public async Task SendToTerminalAndEmail();
public async Task SendToTerminalAndEmail(CancellationToken cancellationToken);

Public Sub SendToTerminalAndEmail()

Async Version
Public Sub SendToTerminalAndEmail() As Task
Public Sub SendToTerminalAndEmail(cancellationToken As CancellationToken) As Task

Remarks

This method is similar to Send but requests also that the message is sent to the terminal of the users as well, if they are logged on and accept terminal messages. This method requires that AllowExtensions is set to True and is not supported by all mail relays.

SendToTerminalOnly Method (SMTP Component)

This method sends to terminal only.

Syntax

C#
VB.NET

public void SendToTerminalOnly();

Async Version
public async Task SendToTerminalOnly();
public async Task SendToTerminalOnly(CancellationToken cancellationToken);

Public Sub SendToTerminalOnly()

Async Version
Public Sub SendToTerminalOnly() As Task
Public Sub SendToTerminalOnly(cancellationToken As CancellationToken) As Task

Remarks

This method is similar to Send but requests instead that the message is sent to the user's terminal. An exception with the server's response is raised if the user is not logged in or does not accept terminal messages. This method requires that AllowExtensions is set to True and is not supported by all mail relays.

SendToTerminalOrEmail Method (SMTP Component)

This method sends to terminal or email.

Syntax

C#
VB.NET

public void SendToTerminalOrEmail();

Async Version
public async Task SendToTerminalOrEmail();
public async Task SendToTerminalOrEmail(CancellationToken cancellationToken);

Public Sub SendToTerminalOrEmail()

Async Version
Public Sub SendToTerminalOrEmail() As Task
Public Sub SendToTerminalOrEmail(cancellationToken As CancellationToken) As Task

Remarks

This method is similar to Send but requests instead that the message is first sent to the user's terminal. If the user is not logged in or does not accept terminal messages, the message is sent to his or her mailbox. This method requires that AllowExtensions is set to True and is not supported by all mail relays.

SetMessageStream Method (SMTP Component)

This method sets the stream to be uploaded to the server as part of the message.

Syntax

C#
VB.NET

public void SetMessageStream(System.IO.Stream messageStream);

Async Version
public async Task SetMessageStream(System.IO.Stream messageStream);
public async Task SetMessageStream(System.IO.Stream messageStream, CancellationToken cancellationToken);

Public Sub SetMessageStream(ByVal MessageStream As System.IO.Stream)

Async Version
Public Sub SetMessageStream(ByVal MessageStream As System.IO.Stream) As Task
Public Sub SetMessageStream(ByVal MessageStream As System.IO.Stream, cancellationToken As CancellationToken) As Task

Remarks

This method sets the stream to be uploaded to the server as part of the message. If an upload stream is set before the Send method is called, the content of the stream will be read by the component and uploaded to the server. The stream should be open and normally set to position 0. The component will automatically close this stream if CloseStreamAfterTransfer is set to True (default). If the stream is closed, you will need to call this method again before calling Send again. The content of the stream will be read from the current position all the way to the end.

Note: This method and LocalFile will reset the other.

Verify Method (SMTP Component)

This method sends a verification request to the SMTP server.

Syntax

C#
VB.NET

public void Verify(string emailAddress);

Async Version
public async Task Verify(string emailAddress);
public async Task Verify(string emailAddress, CancellationToken cancellationToken);

Public Sub Verify(ByVal EmailAddress As String)

Async Version
Public Sub Verify(ByVal EmailAddress As String) As Task
Public Sub Verify(ByVal EmailAddress As String, cancellationToken As CancellationToken) As Task

Remarks

This method asks the MailServer to verify the email address provided in the 'EmailAddress' parameter.

ConnectionStatus Event (SMTP Component)

Fired to indicate changes in the connection state.

Syntax

C#
VB.NET

public event OnConnectionStatusHandler OnConnectionStatus;

public delegate void OnConnectionStatusHandler(object sender, SMTPConnectionStatusEventArgs e);

public class SMTPConnectionStatusEventArgs : EventArgs {
  public string ConnectionEvent { get; }
  public int StatusCode { get; }
  public string Description { get; }
}

Public Event OnConnectionStatus As OnConnectionStatusHandler

Public Delegate Sub OnConnectionStatusHandler(sender As Object, e As SMTPConnectionStatusEventArgs)

Public Class SMTPConnectionStatusEventArgs Inherits EventArgs
  Public ReadOnly Property ConnectionEvent As String
  Public ReadOnly Property StatusCode As Integer
  Public ReadOnly Property Description As String
End Class

Remarks

This event is fired when the connection state changes: for example, completion of a firewall or proxy connection or completion of a security handshake.

The ConnectionEvent parameter indicates the type of connection event. Values may include the following:


	Firewall connection complete.
	Secure Sockets Layer (SSL) or S/Shell handshake complete (where applicable).
	Remote host connection complete.
	Remote host disconnected.
	SSL or S/Shell connection broken.
	Firewall host disconnected.

StatusCode has the error code returned by the Transmission Control Protocol (TCP)/IP stack. Description contains a description of this code. The value of StatusCode is equal to the value of the error.

EndTransfer Event (SMTP Component)

This event is fired when the message text completes transferring.

Syntax

C#
VB.NET

public event OnEndTransferHandler OnEndTransfer;

public delegate void OnEndTransferHandler(object sender, SMTPEndTransferEventArgs e);

public class SMTPEndTransferEventArgs : EventArgs {
  public int Direction { get; }
}

Public Event OnEndTransfer As OnEndTransferHandler

Public Delegate Sub OnEndTransferHandler(sender As Object, e As SMTPEndTransferEventArgs)

Public Class SMTPEndTransferEventArgs Inherits EventArgs
  Public ReadOnly Property Direction As Integer
End Class

Remarks

If MessageText is not empty, the EndTransfer event is fired when the MessageText finishes transferring from the local host to the MailServer. If MessageText is empty, the event is not fired.

If a file is attached to the MessageText via the AttachedFile property, then EndTransfer fires again when the file finishes transferring. For more information, go to the description of the AttachedFile property.

The Direction parameter shows whether the client (0) or the server (1) is sending the data.

Error Event (SMTP Component)

Fired when information is available about errors during data delivery.

Syntax

C#
VB.NET

public event OnErrorHandler OnError;

public delegate void OnErrorHandler(object sender, SMTPErrorEventArgs e);

public class SMTPErrorEventArgs : EventArgs {
  public int ErrorCode { get; }
  public string Description { get; }
}

Public Event OnError As OnErrorHandler

Public Delegate Sub OnErrorHandler(sender As Object, e As SMTPErrorEventArgs)

Public Class SMTPErrorEventArgs Inherits EventArgs
  Public ReadOnly Property ErrorCode As Integer
  Public ReadOnly Property Description As String
End Class

Remarks

The Error event is fired in case of exceptional conditions during message processing. Normally the component throws an exception.

The ErrorCode parameter contains an error code, and the Description parameter contains a textual description of the error. For a list of valid error codes and their descriptions, please refer to the Error Codes section.

Expand Event (SMTP Component)

This event is fired for every email address returned by the server when the Expand method is called.

Syntax

C#
VB.NET

public event OnExpandHandler OnExpand;

public delegate void OnExpandHandler(object sender, SMTPExpandEventArgs e);

public class SMTPExpandEventArgs : EventArgs {
  public string Address { get; }
}

Public Event OnExpand As OnExpandHandler

Public Delegate Sub OnExpandHandler(sender As Object, e As SMTPExpandEventArgs)

Public Class SMTPExpandEventArgs Inherits EventArgs
  Public ReadOnly Property Address As String
End Class

Remarks

This event is fired for every email address as returned by the mail server when the Expand method is called.

The Address parameter may contain a name and an email address, or just an email address, suitable for any of the addressing properties.

PITrail Event (SMTP Component)

This event traces the commands sent to the mail server, and the respective replies.

Syntax

C#
VB.NET

public event OnPITrailHandler OnPITrail;

public delegate void OnPITrailHandler(object sender, SMTPPITrailEventArgs e);

public class SMTPPITrailEventArgs : EventArgs {
  public int Direction { get; }
  public string Message { get; }
}

Public Event OnPITrail As OnPITrailHandler

Public Delegate Sub OnPITrailHandler(sender As Object, e As SMTPPITrailEventArgs)

Public Class SMTPPITrailEventArgs Inherits EventArgs
  Public ReadOnly Property Direction As Integer
  Public ReadOnly Property Message As String
End Class

Remarks

The PITrail event is useful for debugging purposes. It shows all of the interaction between the client and the server, line by line, except for message header and body transfers.

The Message parameter contains the full text of the message. The Direction parameter shows the originator of the message:


0 (Client)	The `Message` originates from the client.
1 (Server)	The `Message` originates from the server.
2 (Info)	The `Message` is an informative message originating from the client software (the component code).

SSLServerAuthentication Event (SMTP Component)

Fired after the server presents its certificate to the client.

Syntax

C#
VB.NET

public event OnSSLServerAuthenticationHandler OnSSLServerAuthentication;

public delegate void OnSSLServerAuthenticationHandler(object sender, SMTPSSLServerAuthenticationEventArgs e);

public class SMTPSSLServerAuthenticationEventArgs : EventArgs {
  public string CertEncoded { get; }
  public byte[] CertEncodedB { get; }
  public string CertSubject { get; }
  public string CertIssuer { get; }
  public string Status { get; }
  public bool Accept { get; set; }
}

Public Event OnSSLServerAuthentication As OnSSLServerAuthenticationHandler

Public Delegate Sub OnSSLServerAuthenticationHandler(sender As Object, e As SMTPSSLServerAuthenticationEventArgs)

Public Class SMTPSSLServerAuthenticationEventArgs Inherits EventArgs
  Public ReadOnly Property CertEncoded As String
  Public ReadOnly Property CertEncodedB As Byte()
  Public ReadOnly Property CertSubject As String
  Public ReadOnly Property CertIssuer As String
  Public ReadOnly Property Status As String
  Public Property Accept As Boolean
End Class

Remarks

During this event, the client can decide whether or not to continue with the connection process. The Accept parameter is a recommendation on whether to continue or close the connection. This is just a suggestion: application software must use its own logic to determine whether or not to continue.

When Accept is False, Status shows why the verification failed (otherwise, Status contains the string OK). If it is decided to continue, you can override and accept the certificate by setting the Accept parameter to True.

SSLStatus Event (SMTP Component)

Fired when secure connection progress messages are available.

Syntax

C#
VB.NET

public event OnSSLStatusHandler OnSSLStatus;

public delegate void OnSSLStatusHandler(object sender, SMTPSSLStatusEventArgs e);

public class SMTPSSLStatusEventArgs : EventArgs {
  public string Message { get; }
}

Public Event OnSSLStatus As OnSSLStatusHandler

Public Delegate Sub OnSSLStatusHandler(sender As Object, e As SMTPSSLStatusEventArgs)

Public Class SMTPSSLStatusEventArgs Inherits EventArgs
  Public ReadOnly Property Message As String
End Class

Remarks

The event is fired for informational and logging purposes only. This event tracks the progress of the connection.

StartTransfer Event (SMTP Component)

This event is fired when the message text starts transferring.

Syntax

C#
VB.NET

public event OnStartTransferHandler OnStartTransfer;

public delegate void OnStartTransferHandler(object sender, SMTPStartTransferEventArgs e);

public class SMTPStartTransferEventArgs : EventArgs {
  public int Direction { get; }
}

Public Event OnStartTransfer As OnStartTransferHandler

Public Delegate Sub OnStartTransferHandler(sender As Object, e As SMTPStartTransferEventArgs)

Public Class SMTPStartTransferEventArgs Inherits EventArgs
  Public ReadOnly Property Direction As Integer
End Class

Remarks

If MessageText is not empty, the StartTransfer event is fired when the MessageText starts transferring from the local host to the MailServer. If MessageText is empty, the event is not fired.

If a file is attached to the MessageText via the AttachedFile property, then StartTransfer fires again when the file starts transferring. Please go to the description of the AttachedFile property for more information.

The Direction parameter shows whether the client (0) or the server (1) is sending the data.

Transfer Event (SMTP Component)

This event is fired when the message text is transferred to MailServer .

Syntax

C#
VB.NET

public event OnTransferHandler OnTransfer;

public delegate void OnTransferHandler(object sender, SMTPTransferEventArgs e);

public class SMTPTransferEventArgs : EventArgs {
  public int Direction { get; }
  public long BytesTransferred { get; }
  public int PercentDone { get; }
  public string Text { get; }
  public byte[] TextB { get; }
}

Public Event OnTransfer As OnTransferHandler

Public Delegate Sub OnTransferHandler(sender As Object, e As SMTPTransferEventArgs)

Public Class SMTPTransferEventArgs Inherits EventArgs
  Public ReadOnly Property Direction As Integer
  Public ReadOnly Property BytesTransferred As Long
  Public ReadOnly Property PercentDone As Integer
  Public ReadOnly Property Text As String
  Public ReadOnly Property TextB As Byte()
End Class

Remarks

One or more Transfer events are fired during message delivery. Messages consist of MessageText and an optional AttachedFile. The BytesTransferred parameter shows the number of bytes sent starting from the beginning of MessageText or AttachedFile.

Text contains the current portion of the message being sent.

The Direction parameter shows whether the client (0) or the server (1) is sending the data.

The PercentDone parameter shows the progress of the transfer in the corresponding direction. If PercentDone can not be calculated the value will be -1.

Note: Events are not re-entrant. Performing time-consuming operations within this event will prevent it from firing again in a timely manner and may affect overall performance.

Certificate Type

This is the digital certificate being used.

Remarks

This type describes the current digital certificate. The certificate may be a public or private key. The fields are used to identify or select certificates.

The following fields are available:

Fields

EffectiveDate
string (read-only)
Default: ""

The date on which this certificate becomes valid. Before this date, it is not valid. The date is localized to the system's time zone. The following example illustrates the format of an encoded date:

23-Jan-2000 15:00:00.

ExpirationDate
string (read-only)
Default: ""

The date on which the certificate expires. After this date, the certificate will no longer be valid. The date is localized to the system's time zone. The following example illustrates the format of an encoded date:

23-Jan-2001 15:00:00.

ExtendedKeyUsage
string (read-only)
Default: ""

A comma-delimited list of extended key usage identifiers. These are the same as ASN.1 object identifiers (OIDs).

Fingerprint
string (read-only)
Default: ""

The hex-encoded, 16-byte MD5 fingerprint of the certificate. This property is primarily used for keys which do not have a corresponding X.509 public certificate, such as PEM keys that only contain a private key. It is commonly used for SSH keys.

The following example illustrates the format: bc:2a:72:af:fe:58:17:43:7a:5f:ba:5a:7c:90:f7:02

FingerprintSHA1
string (read-only)
Default: ""

The hex-encoded, 20-byte SHA-1 fingerprint of the certificate. This property is primarily used for keys which do not have a corresponding X.509 public certificate, such as PEM keys that only contain a private key. It is commonly used for SSH keys.

The following example illustrates the format: 30:7b:fa:38:65:83:ff:da:b4:4e:07:3f:17:b8:a4:ed:80:be:ff:84

FingerprintSHA256
string (read-only)
Default: ""

The hex-encoded, 32-byte SHA-256 fingerprint of the certificate. This property is primarily used for keys which do not have a corresponding X.509 public certificate, such as PEM keys that only contain a private key. It is commonly used for SSH keys.

The following example illustrates the format: 6a:80:5c:33:a9:43:ea:b0:96:12:8a:64:96:30:ef:4a:8a:96:86:ce:f4:c7:be:10:24:8e:2b:60:9e:f3:59:53

Issuer
string (read-only)
Default: ""

The issuer of the certificate. This field contains a string representation of the name of the issuing authority for the certificate.

PrivateKey
string (read-only)
Default: ""

The private key of the certificate (if available). The key is provided as PEM/Base64-encoded data.

Note: The PrivateKey may be available but not exportable. In this case, PrivateKey returns an empty string.

PrivateKeyAvailable
bool (read-only)
Default: False

Whether a PrivateKey is available for the selected certificate. If PrivateKeyAvailable is True, the certificate may be used for authentication purposes (e.g., server authentication).

PrivateKeyContainer
string (read-only)
Default: ""

The name of the PrivateKey container for the certificate (if available). This functionality is available only on Windows platforms.

PublicKey
string (read-only)
Default: ""

The public key of the certificate. The key is provided as PEM/Base64-encoded data.

PublicKeyAlgorithm
string (read-only)
Default: ""

The textual description of the certificate's public key algorithm. The property contains either the name of the algorithm (e.g., "RSA" or "RSA_DH") or an object identifier (OID) string representing the algorithm.

PublicKeyLength
int (read-only)
Default: 0

The length of the certificate's public key (in bits). Common values are 512, 1024, and 2048.

SerialNumber
string (read-only)
Default: ""

The serial number of the certificate encoded as a string. The number is encoded as a series of hexadecimal digits, with each pair representing a byte of the serial number.

SignatureAlgorithm
string (read-only)
Default: ""

The text description of the certificate's signature algorithm. The property contains either the name of the algorithm (e.g., "RSA" or "RSA_MD5RSA") or an object identifier (OID) string representing the algorithm.

Store
string
Default: "MY"

The name of the certificate store for the client certificate.

The StoreType field denotes the type of the certificate store specified by Store. If the store is password-protected, specify the password in StorePassword.

Store is used in conjunction with the Subject field to specify client certificates. If Store has a value, and Subject or Encoded is set, a search for a certificate is initiated. Please see the Subject field for details.

Designations of certificate stores are platform dependent.

The following designations are the most common User and Machine certificate stores in Windows:


MY	A certificate store holding personal certificates with their associated private keys.
CA	Certifying authority certificates.
ROOT	Root certificates.

When the certificate store type is cstPFXFile, this property must be set to the name of the file. When the type is cstPFXBlob, the property must be set to the binary contents of a PFX file (i.e., PKCS#12 certificate store).

StoreB
byte []
Default: "MY"

The name of the certificate store for the client certificate.

The StoreType field denotes the type of the certificate store specified by Store. If the store is password-protected, specify the password in StorePassword.

Designations of certificate stores are platform dependent.

The following designations are the most common User and Machine certificate stores in Windows:


MY	A certificate store holding personal certificates with their associated private keys.
CA	Certifying authority certificates.
ROOT	Root certificates.

StorePassword
string
Default: ""

If the type of certificate store requires a password, this field is used to specify the password needed to open the certificate store.

StoreType
CertStoreTypes
Default: 0

The type of certificate store for this certificate.

The component supports both public and private keys in a variety of formats. When the cstAuto value is used, the component will automatically determine the type. This field can take one of the following values:


0 (cstUser - default)	For Windows, this specifies that the certificate store is a certificate store owned by the current user. Note: This store type is not available in Java.
1 (cstMachine)	For Windows, this specifies that the certificate store is a machine store. Note: This store type is not available in Java.
2 (cstPFXFile)	The certificate store is the name of a PFX (PKCS#12) file containing certificates.
3 (cstPFXBlob)	The certificate store is a string (binary or Base64-encoded) representing a certificate store in PFX (PKCS#12) format.
4 (cstJKSFile)	The certificate store is the name of a Java Key Store (JKS) file containing certificates. Note: This store type is only available in Java.
5 (cstJKSBlob)	The certificate store is a string (binary or Base64-encoded) representing a certificate store in Java Key Store (JKS) format. Note: This store type is only available in Java.
6 (cstPEMKeyFile)	The certificate store is the name of a PEM-encoded file that contains a private key and an optional certificate.
7 (cstPEMKeyBlob)	The certificate store is a string (binary or Base64-encoded) that contains a private key and an optional certificate.
8 (cstPublicKeyFile)	The certificate store is the name of a file that contains a PEM- or DER-encoded public key certificate.
9 (cstPublicKeyBlob)	The certificate store is a string (binary or Base64-encoded) that contains a PEM- or DER-encoded public key certificate.
10 (cstSSHPublicKeyBlob)	The certificate store is a string (binary or Base64-encoded) that contains an SSH-style public key.
11 (cstP7BFile)	The certificate store is the name of a PKCS#7 file containing certificates.
12 (cstP7BBlob)	The certificate store is a string (binary) representing a certificate store in PKCS#7 format.
13 (cstSSHPublicKeyFile)	The certificate store is the name of a file that contains an SSH-style public key.
14 (cstPPKFile)	The certificate store is the name of a file that contains a PPK (PuTTY Private Key).
15 (cstPPKBlob)	The certificate store is a string (binary) that contains a PPK (PuTTY Private Key).
16 (cstXMLFile)	The certificate store is the name of a file that contains a certificate in XML format.
17 (cstXMLBlob)	The certificate store is a string that contains a certificate in XML format.
18 (cstJWKFile)	The certificate store is the name of a file that contains a JWK (JSON Web Key).
19 (cstJWKBlob)	The certificate store is a string that contains a JWK (JSON Web Key).
21 (cstBCFKSFile)	The certificate store is the name of a file that contains a BCFKS (Bouncy Castle FIPS Key Store). Note: This store type is only available in Java and .NET.
22 (cstBCFKSBlob)	The certificate store is a string (binary or Base64-encoded) representing a certificate store in BCFKS (Bouncy Castle FIPS Key Store) format. Note: This store type is only available in Java and .NET.
23 (cstPKCS11)	The certificate is present on a physical security key accessible via a PKCS#11 interface. To use a security key, the necessary data must first be collected using the CertMgr component. The ListStoreCertificates method may be called after setting CertStoreType to `cstPKCS11`, CertStorePassword to the PIN, and CertStore to the full path of the PKCS#11 DLL. The certificate information returned in the CertList event's `CertEncoded` parameter may be saved for later use. When using a certificate, pass the previously saved security key information as the Store and set StorePassword to the PIN. Code Example. SSH Authentication with Security Key: `certmgr.CertStoreType = CertStoreTypes.cstPKCS11; certmgr.OnCertList += (s, e) => { secKeyBlob = e.CertEncoded; }; certmgr.CertStore = @"C:\Program Files\OpenSC Project\OpenSC\pkcs11\opensc-pkcs11.dll"; certmgr.CertStorePassword = "123456"; //PIN certmgr.ListStoreCertificates(); sftp.SSHCert = new Certificate(CertStoreTypes.cstPKCS11, secKeyBlob, "123456", "*"); sftp.SSHUser = "test"; sftp.SSHLogon("myhost", 22);`
99 (cstAuto)	The store type is automatically detected from the input data. This setting may be used with both public and private keys and can detect any of the supported formats automatically.

SubjectAltNames
string (read-only)
Default: ""

Comma-separated lists of alternative subject names for the certificate.

ThumbprintMD5
string (read-only)
Default: ""

The MD5 hash of the certificate. It is primarily used for X.509 certificates. If the hash does not already exist, it is automatically computed.

ThumbprintSHA1
string (read-only)
Default: ""

The SHA-1 hash of the certificate. It is primarily used for X.509 certificates. If the hash does not already exist, it is automatically computed.

ThumbprintSHA256
string (read-only)
Default: ""

The SHA-256 hash of the certificate. It is primarily used for X.509 certificates. If the hash does not already exist, it is automatically computed.

Usage
string (read-only)
Default: ""

The text description of UsageFlags.

This value will be one or more of the following strings and will be separated by commas:

Digital Signature
Non-Repudiation
Key Encipherment
Data Encipherment
Key Agreement
Certificate Signing
CRL Signing
Encipher Only

If the provider is OpenSSL, the value is a comma-separated list of X.509 certificate extension names.

UsageFlags
int (read-only)
Default: 0

The flags that show intended use for the certificate. The value of UsageFlags is a combination of the following flags:


0x80	Digital Signature
0x40	Non-Repudiation
0x20	Key Encipherment
0x10	Data Encipherment
0x08	Key Agreement
0x04	Certificate Signing
0x02	CRL Signing
0x01	Encipher Only

Please see the Usage field for a text representation of UsageFlags.

This functionality currently is not available when the provider is OpenSSL.

Version
string (read-only)
Default: ""

The certificate's version number. The possible values are the strings "V1", "V2", and "V3".

Subject
string
Default: ""

The subject of the certificate used for client authentication.

This field will be populated with the full subject of the loaded certificate. When loading a certificate, the subject is used to locate the certificate in the store.

If an exact match is not found, the store is searched for subjects containing the value of the property.

If a match is still not found, the property is set to an empty string, and no certificate is selected.

The special value "*" picks a random certificate in the certificate store.

The certificate subject is a comma-separated list of distinguished name fields and values. For instance, "CN=www.server.com, OU=test, C=US, E=support@nsoftware.com". Common fields and their meanings are as follows:


Field	Meaning
CN	Common Name. This is commonly a hostname like www.server.com.
O	Organization
OU	Organizational Unit
L	Locality
S	State
C	Country
E	Email Address

If a field value contains a comma, it must be quoted.

Encoded
string
Default: ""

The certificate (PEM/Base64 encoded). This field is used to assign a specific certificate. The Store and Subject fields also may be used to specify a certificate.

When Encoded is set, a search is initiated in the current Store for the private key of the certificate. If the key is found, Subject is updated to reflect the full subject of the selected certificate; otherwise, Subject is set to an empty string.

EncodedB
byte []
Default: ""

The certificate (PEM/Base64 encoded). This field is used to assign a specific certificate. The Store and Subject fields also may be used to specify a certificate.

Constructors

C#
VB.NET

public Certificate();

Public Certificate()

Creates a instance whose properties can be set. This is useful for use with when generating new certificates.

C#
VB.NET

public Certificate(string certificateFile);

Public Certificate(ByVal CertificateFile As String)

Opens CertificateFile and reads out the contents as an X.509 public key.

C#
VB.NET

public Certificate(byte[] encoded);

Public Certificate(ByVal Encoded As Byte())

Parses Encoded as an X.509 public key.

C#
VB.NET

public Certificate(CertStoreTypes storeType, string store, string storePassword, string subject);

Public Certificate(ByVal StoreType As CertStoreTypes, ByVal Store As String, ByVal StorePassword As String, ByVal Subject As String)

StoreType identifies the type of certificate store to use. See for descriptions of the different certificate stores. Store is a file containing the certificate store. StorePassword is the password used to protect the store.

After the store has been successfully opened, the component will attempt to find the certificate identified by Subject . This can be either a complete or a substring match of the X.509 certificate's subject Distinguished Name (DN). The Subject parameter can also take an MD5, SHA-1, or SHA-256 thumbprint of the certificate to load in a "Thumbprint=value" format.

C#
VB.NET

public Certificate(CertStoreTypes storeType, string store, string storePassword, string subject, string configurationString);

Public Certificate(ByVal StoreType As CertStoreTypes, ByVal Store As String, ByVal StorePassword As String, ByVal Subject As String, ByVal ConfigurationString As String)

ConfigurationString is a newline-separated list of name-value pairs that may be used to modify the default behavior. Possible values include "PersistPFXKey", which shows whether or not the PFX key is persisted after performing operations with the private key. This correlates to the PKCS12_NO_PERSIST_KEY CryptoAPI option. The default value is True (the key is persisted). "Thumbprint" - an MD5, SHA-1, or SHA-256 thumbprint of the certificate to load. When specified, this value is used to select the certificate in the store. This is applicable to the cstUser , cstMachine , cstPublicKeyFile , and cstPFXFile store types. "UseInternalSecurityAPI" shows whether the platform (default) or the internal security API is used when performing certificate-related operations.

C#
VB.NET

public Certificate(CertStoreTypes storeType, string store, string storePassword, byte[] encoded);

Public Certificate(ByVal StoreType As CertStoreTypes, ByVal Store As String, ByVal StorePassword As String, ByVal Encoded As Byte())

After the store has been successfully opened, the component will load Encoded as an X.509 certificate and search the opened store for a corresponding private key.

C#
VB.NET

public Certificate(CertStoreTypes storeType, byte[] store, string storePassword, string subject);

Public Certificate(ByVal StoreType As CertStoreTypes, ByVal Store As Byte(), ByVal StorePassword As String, ByVal Subject As String)

StoreType identifies the type of certificate store to use. See for descriptions of the different certificate stores. Store is a byte array containing the certificate data. StorePassword is the password used to protect the store.

C#
VB.NET

public Certificate(CertStoreTypes storeType, byte[] store, string storePassword, string subject, string configurationString);

Public Certificate(ByVal StoreType As CertStoreTypes, ByVal Store As Byte(), ByVal StorePassword As String, ByVal Subject As String, ByVal ConfigurationString As String)

C#
VB.NET

public Certificate(CertStoreTypes storeType, byte[] store, string storePassword, byte[] encoded);

Public Certificate(ByVal StoreType As CertStoreTypes, ByVal Store As Byte(), ByVal StorePassword As String, ByVal Encoded As Byte())

After the store has been successfully opened, the component will load Encoded as an X.509 certificate and search the opened store for a corresponding private key.

Firewall Type

The firewall the component will connect through.

Remarks

When connecting through a firewall, this type is used to specify different properties of the firewall, such as the firewall Host and the FirewallType.

The following fields are available:

Fields

AutoDetect
bool
Default: False

Whether to automatically detect and use firewall system settings, if available.

FirewallType
FirewallTypes
Default: 0

The type of firewall to connect through. The applicable values are as follows:


fwNone (0)	No firewall (default setting).
fwTunnel (1)	Connect through a tunneling proxy. Port is set to 80.
fwSOCKS4 (2)	Connect through a SOCKS4 Proxy. Port is set to 1080.
fwSOCKS5 (3)	Connect through a SOCKS5 Proxy. Port is set to 1080.
fwSOCKS4A (10)	Connect through a SOCKS4A Proxy. Port is set to 1080.

Host
string
Default: ""

The name or IP address of the firewall (optional). If a Host is given, the requested connections will be authenticated through the specified firewall when connecting.

If this field is set to a Domain Name, a DNS request is initiated. Upon successful termination of the request, this field is set to the corresponding address. If the search is not successful, the component throws an exception.

Password
string
Default: ""

A password if authentication is to be used when connecting through the firewall. If Host is specified, the User and Password fields are used to connect and authenticate to the given firewall. If the authentication fails, the component throws an exception.

Port
int
Default: 0

The Transmission Control Protocol (TCP) port for the firewall Host. See the description of the Host field for details.

Note: This field is set automatically when FirewallType is set to a valid value. See the description of the FirewallType field for details.

User
string
Default: ""

A username if authentication is to be used when connecting through a firewall. If Host is specified, this field and the Password field are used to connect and authenticate to the given Firewall. If the authentication fails, the component throws an exception.

Constructors

C#
VB.NET

public Firewall();

Public Firewall()

Header Type

This is an HTTP header as it is received from the server.

Remarks

When a header is received through a Header event, it is parsed into a Header type. This type contains a Field, and its corresponding Value.

The following fields are available:

Field

Value

Fields

Field
string
Default: ""

This field contains the name of the HTTP Header (this is the same case as it is delivered).

Value
string
Default: ""

This field contains the Header contents.

Constructors

C#
VB.NET

public Header();

Public Header()

C#
VB.NET

public Header(string field, string value);

Public Header(ByVal Field As String, ByVal Value As String)

MessageRecipient Type

This types describes the message recipient.

Remarks

This type describes who the message is sent to. It includes fields to denote the name and email address of the recipient of the message. The type of recipient must also be specified if the component is sending the message.

The following fields are available:

Fields

Address
string
Default: ""

This field contains the email address of the recipient.

Name
string
Default: ""

This field contains the name of the recipient.

Options
string
Default: ""

This field contains the recipient sending options (used only by SMTP). This must be a string of RFC-compliant recipient options (used by SMTP).

One type of option is a delivery status notification sent per recipient, which is specified by RFC 1891.

component.MessageRecipients(0).Options = "NOTIFY SUCCESS,FAILURE,DELAY";

RecipientType
EmailRecipientTypes
Default: 0

This field contains the recipient type: To, Cc, or Bcc.

Constructors

C#
VB.NET

public MessageRecipient();

Public MessageRecipient()

C#
VB.NET

public MessageRecipient(string address);

Public MessageRecipient(ByVal Address As String)

C#
VB.NET

public MessageRecipient(string address, int recipientType);

Public MessageRecipient(ByVal Address As String, ByVal RecipientType As Integer)

Config Settings (SMTP Component)

The component accepts one or more of the following configuration settings. Configuration settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the component, access to these internal properties is provided through the Config method.

SMTP Config Settings

AllowEmptyTo: If set to True, then the SendTo property is not required.

Normally, the SendTo property is required to send a message. If AllowEmptyTo is True, then this is not the case, and messages can be sent with just one or both of Cc and BCc set.

AuthorizationIdentity: The value to use as the authorization identity when SASL authentication is used.

When AuthMechanism is set to amXOAUTH2, you may use this configuration setting to specify an authorization identity to be used when authenticating. In the case of amXOAUTH2, this should be your OAUTH authorization string. For instance:

Bearer ya29.AHES6ZRmS-8xPbpGetC1VbABJIBRdKm-c4X7wMVGAbgxdGt5q8Ts3Q

Note: When using amXOAUTH2, User must be specified, but Password is not required.

Charset: When set, the message headers will be encoded using the specified Charset.

This configuration setting is used to specify the "charset" to be used to encode the message headers. For example, to use UTF-8 you can set this property to "UTF-8". The default value is "" (empty string) in which case the headers will not be encoded.

FoldHeaders: Tells the component whether to fold the headers.

If True, the component will fold the headers if the headers are over a certain length. If False, the headers will be on one line regardless of length.

Note: This is True by default.

Hello: The argument for HELO (herald) command to the server (defaults to local host name).

The Hello property specifies a string to send to the MailServer at connection time as an argument to the SMTP HELO command. This generally identifies the host sending mail, and that is why the Hello property defaults to the name of the local host. The property is provided in case the component does not accept the default value and a custom value (e.g., a fully qualified domain name) must be sent.

If AllowExtensions is True, the EHLO command will be sent instead of the HELO command.

KeepQueue: If set to True, queued files are not deleted after a successful send.

Normally, ProcessQueue deletes queued files after processing them. If KeepQueue is True, then the file extension is instead changed to ".sent" and the files are not deleted.

MaxHeaderLength: Maximum length for headers to avoid line folding (default 80).

The MaxHeaderLength specifies the maximum line length supported by the mail delivery system. Any headers longer than MaxHeaderLength are folded as specified in RFC 822.

It is generally a good idea to use a MaxHeaderLength of less than 100 bytes, although different mail relays and mail servers have different requirements for header lengths.

MessageHeadersString: String representation of RFC822-encoded headers of the message.

This setting holds the full headers of the message in RFC 822 format. Use this along with TransferText to store the entire message in RFC 822 format.

Example: smtp1.Send(); string rawMsg = smtp1.Config("MessageHeadersString") + smtp1.Config("TransferText");

MessageIdAlgorithm: Determines the algorithm used to hash the random MessageId.

The MessageIdAlgorithm specifies which algorithm to use in the hash for the MessageId when the property is set to "*". The default value is "SHA1".

Possible values are as follows:

"MD5"
"SHA1" (default)
"SHA256"

OtherHeaders: An RFC 822 compliant string consisting of extra headers.

This is the same as the OtherHeaders property. This configuration setting is exposed for use by components that are inherited from SMTP.

ReturnPath: Sets the Return-Path to be used for sending email.

This is the same as the ReturnPath property. This configuration setting is exposed for use by components that are inherited from SMTP.

SendRSET: Whether to send RSET command.

By default, the component will periodically send the RSET command to the server. Changing this configuration setting to False will prevent the RSET command from being sent. This can be useful when interacting with some servers that do not respond properly to the RSET command.

StopOnBccErrors: Instructs the component to stop sending the message if the server does not acknowledge any of the BCCs.

If this configuration setting is set to True, the component will fail the moment the server does not acknowledge a Bcc address. If it is set to False, an error will be fired for every Bcc that is not recognized by the server, but the message will be sent to the rest of the recipients. The default value is False.

StopOnCcErrors: Instructs the component to stop sending the message if the server does not acknowledge any of the CCs.

If this configuration setting is set to True, the component will fail the moment the server does not acknowledge a Cc address. If it is set to False, an error will be fired for every Cc that is not recognized by the server, but the message will be sent to the rest of the recipients. The default value is True.

StopOnToErrors: Instructs the component to stop sending the message if the server does not acknowledge any of the TOs.

If this configuration setting is set to True, the component will fail the moment the server does not acknowledge a To address. If it is set to False, an error will be fired for every To that is not recognized by the server, but the message will be sent to the rest of the recipients. The default value is True.

TransferText: String representation of RFC822-encoded body of the message.

This configuration setting holds the full body of the message in RFC 822 format. Use this along with MessageHeadersString to store the entire message in RFC 822 format.

Example: smtp1.Send(); string rawMsg = smtp1.Config("MessageHeadersString") + smtp1.Config("TransferText");

TCPClient Config Settings

CloseStreamAfterTransfer: If true, the component will close the upload or download stream after the transfer.

This configuration setting determines whether the input or output stream is closed after the transfer completes. When set to True (default), all streams will be closed after a transfer is completed. To keep streams open after the transfer of data, set this to False. The default value is True.

ConnectionTimeout: Sets a separate timeout value for establishing a connection.

When set, this configuration setting allows you to specify a different timeout value for establishing a connection. Otherwise, the component will use Timeout for establishing a connection and transmitting/receiving data.

FirewallAutoDetect: Tells the component whether or not to automatically detect and use firewall system settings, if available.

This configuration setting is provided for use by components that do not directly expose Firewall properties.

FirewallHost: Name or IP address of firewall (optional).

If a FirewallHost is given, requested connections will be authenticated through the specified firewall when connecting.

If the FirewallHost setting is set to a Domain Name, a DNS request is initiated. Upon successful termination of the request, the FirewallHost setting is set to the corresponding address. If the search is not successful, an error is returned.

Note: This setting is provided for use by components that do not directly expose Firewall properties.

FirewallListener: If true, the component binds to a SOCKS firewall as a server (TCPClient only).

This entry is for TCPClient only and does not work for other components that descend from TCPClient.

If this entry is set, the component acts as a server. RemoteHost and RemotePort are used to tell the SOCKS firewall in which address and port to listen to. The firewall rules may ignore RemoteHost, and it is recommended that RemoteHost be set to empty string in this case.

RemotePort is the port in which the firewall will listen to. If set to 0, the firewall will select a random port. The binding (address and port) is provided through the ConnectionStatus event.

The connection to the firewall is made by calling the Connect method.

FirewallPassword: Password to be used if authentication is to be used when connecting through the firewall.

If FirewallHost is specified, the FirewallUser and FirewallPassword settings are used to connect and authenticate to the given firewall. If the authentication fails, the component throws an exception.

Note: This setting is provided for use by components that do not directly expose Firewall properties.

FirewallPort: The TCP port for the FirewallHost;.

The FirewallPort is set automatically when FirewallType is set to a valid value.

Note: This configuration setting is provided for use by components that do not directly expose Firewall properties.

FirewallType: Determines the type of firewall to connect through.

Possible values are as follows:


0	No firewall (default setting).
1	Connect through a tunneling proxy. FirewallPort is set to 80.
2	Connect through a SOCKS4 Proxy. FirewallPort is set to 1080.
3	Connect through a SOCKS5 Proxy. FirewallPort is set to 1080.
10	Connect through a SOCKS4A Proxy. FirewallPort is set to 1080.

Note: This setting is provided for use by components that do not directly expose Firewall properties.

FirewallUser: A user name if authentication is to be used connecting through a firewall.

If the FirewallHost is specified, the FirewallUser and FirewallPassword settings are used to connect and authenticate to the Firewall. If the authentication fails, the component throws an exception.

Note: This setting is provided for use by components that do not directly expose Firewall properties.

KeepAliveInterval: The retry interval, in milliseconds, to be used when a TCP keep-alive packet is sent and no response is received.

When set, TCPKeepAlive will automatically be set to True. A TCP keep-alive packet will be sent after a period of inactivity as defined by KeepAliveTime. If no acknowledgment is received from the remote host, the keep-alive packet will be sent again. This configuration setting specifies the interval at which the successive keep-alive packets are sent in milliseconds. This system default if this value is not specified here is 1 second.

Note: This value is not applicable in macOS.

KeepAliveTime: The inactivity time in milliseconds before a TCP keep-alive packet is sent.

When set, TCPKeepAlive will automatically be set to True. By default, the operating system will determine the time a connection is idle before a Transmission Control Protocol (TCP) keep-alive packet is sent. This system default if this value is not specified here is 2 hours. In many cases, a shorter interval is more useful. Set this value to the desired interval in milliseconds.

Linger: When set to True, connections are terminated gracefully.

This property controls how a connection is closed. The default is True.

In the case that Linger is True (default), two scenarios determine how long the connection will linger. In the first, if LingerTime is 0 (default), the system will attempt to send pending data for a connection until the default IP timeout expires.

In the second scenario, if LingerTime is a positive value, the system will attempt to send pending data until the specified LingerTime is reached. If this attempt fails, then the system will reset the connection.

The default behavior (which is also the default mode for stream sockets) might result in a long delay in closing the connection. Although the component returns control immediately, the system could hold system resources until all pending data are sent (even after your application closes).

Setting this property to False forces an immediate disconnection. If you know that the other side has received all the data you sent (e.g., by a client acknowledgment), setting this property to False might be the appropriate course of action.

LingerTime: Time in seconds to have the connection linger.

LingerTime is the time, in seconds, the socket connection will linger. This value is 0 by default, which means it will use the default IP timeout.

LocalHost: The name of the local host through which connections are initiated or accepted.

The LocalHost setting contains the name of the local host as obtained by the gethostname() system call, or if the user has assigned an IP address, the value of that address.

In multihomed hosts (machines with more than one IP interface), setting LocalHost to the value of an interface will make the component initiate connections (or accept in the case of server components) only through that interface.

If the component is connected, the LocalHost setting shows the IP address of the interface through which the connection is made in internet dotted format (aaa.bbb.ccc.ddd). In most cases, this is the address of the local host, except for multihomed hosts (machines with more than one IP interface).

LocalPort: The port in the local host where the component binds.

This configuration setting must be set before a connection is attempted. It instructs the component to bind to a specific port (or communication endpoint) in the local machine.

Setting this to 0 (default) enables the system to choose a port at random. The chosen port will be shown by LocalPort after the connection is established.

LocalPort cannot be changed once a connection is made. Any attempt to set this when a connection is active will generate an error.

This configuration setting is useful when trying to connect to services that require a trusted port on the client side. An example is the remote shell (rsh) service in UNIX systems.

MaxLineLength: The maximum amount of data to accumulate when no EOL is found.

MaxLineLength is the size of an internal buffer, which holds received data while waiting for an EOL string.

If an EOL string is found in the input stream before MaxLineLength bytes are received, the DataIn event is fired with the EOL parameter set to True, and the buffer is reset.

If no EOL is found, and MaxLineLength bytes are accumulated in the buffer, the DataIn event is fired with the EOL parameter set to False, and the buffer is reset.

The minimum value for MaxLineLength is 256 bytes. The default value is 2048 bytes.

MaxTransferRate: The transfer rate limit in bytes per second.

This configuration setting can be used to throttle outbound TCP traffic. Set this to the number of bytes to be sent per second. By default, this is not set and there is no limit.

ProxyExceptionsList: A semicolon separated list of hosts and IPs to bypass when using a proxy.

This configuration setting optionally specifies a semicolon-separated list of hostnames or IP addresses to bypass when a proxy is in use. When requests are made to hosts specified in this property, the proxy will not be used. For instance:

www.google.com;www.nsoftware.com

TCPKeepAlive: Determines whether or not the keep alive socket option is enabled.

If set to True, the socket's keep-alive option is enabled and keep-alive packets will be sent periodically to maintain the connection. Set KeepAliveTime and KeepAliveInterval to configure the timing of the keep-alive packets.

Note: This value is not applicable in Java.

TcpNoDelay: Whether or not to delay when sending packets.

When set to True, the socket will send all data that are ready to send at once. When set to False, the socket will send smaller buffered packets of data at small intervals. This is known as the Nagle algorithm.

By default, this configuration setting is set to False.

UseIPv6: Whether to use IPv6.

When set to 0 (default), the component will use IPv4 exclusively. When set to 1, the component will use IPv6 exclusively. To instruct the component to prefer IPv6 addresses, but use IPv4 if IPv6 is not supported on the system, this setting should be set to 2. The default value is 0. Possible values are as follows:


0	IPv4 only
1	IPv6 only
2	IPv6 with IPv4 fallback

UseNTLMv2: Whether to use NTLM V2.

When authenticating with NTLM, this setting specifies whether NTLM V2 is used. By default this value is False and NTLM V1 will be used. Set this to True to use NTLM V2.

SSL Config Settings

CACertFilePaths: The paths to CA certificate files when using Mono on Unix/Linux.

This configuration setting specifies the paths on disk to certificate authority (CA) certificate files when using Mono on Unix/Linux. It is not applicable in any other circumstances.

The value is formatted as a list of paths separated by semicolons. The component will check for the existence of each file in the order specified. When a file is found, the CA certificates within the file will be loaded and used to determine the validity of server or client certificates.

The default value is as follows:

/etc/ssl/ca-bundle.pem;/etc/pki/tls/certs/ca-bundle.crt;/etc/ssl/certs/ca-certificates.crt;/etc/pki/tls/cacert.pem

LogSSLPackets: Controls whether SSL packets are logged when using the internal security API.

When SSLProvider is set to Internal, this configuration setting controls whether Secure Sockets Layer (SSL) packets should be logged. By default, this configuration setting is False, as it is useful only for debugging purposes.

When enabled, SSL packet logs are output using the SSLStatus event, which will fire each time an SSL packet is sent or received.

Enabling this configuration setting has no effect if SSLProvider is set to Platform.

ReuseSSLSession: Determines if the SSL session is reused.

If set to True, the component will reuse the context if and only if the following criteria are met:

The target host name is the same.
The system cache entry has not expired (default timeout is 10 hours).
The application process that calls the function is the same.
The logon session is the same.
The instance of the component is the same.

SSLCACerts: A newline separated list of CA certificates to be included when performing an SSL handshake.

When SSLProvider is set to Internal, this configuration setting specifies one or more CA certificates to be included with the SSLCert property. Some servers or clients require the entire chain, including CA certificates, to be presented when performing SSL authentication. The value of this configuration setting is a newline-separated (CR/LF) list of certificates. For instance:

-----BEGIN CERTIFICATE-----
MIIEKzCCAxOgAwIBAgIRANTET4LIkxdH6P+CFIiHvTowDQYJKoZIhvcNAQELBQAw
... Intermediate Cert ...
eWHV5OW1K53o/atv59sOiW5K3crjFhsBOd5Q+cJJnU+SWinPKtANXMht+EDvYY2w
F0I1XhM+pKj7FjDr+XNj
-----END CERTIFICATE-----
\r \n
-----BEGIN CERTIFICATE-----
MIIEFjCCAv6gAwIBAgIQetu1SMxpnENAnnOz1P+PtTANBgkqhkiG9w0BAQUFADBp
... Root Cert ...
d8q23djXZbVYiIfE9ebr4g3152BlVCHZ2GyPdjhIuLeH21VbT/dyEHHA
-----END CERTIFICATE-----

SSLCheckCRL: Whether to check the Certificate Revocation List for the server certificate.

This configuration setting specifies whether the component will check the Certificate Revocation List (CRL) specified by the server certificate. If set to 1 or 2, the component will first obtain the list of CRL URLs from the server certificate's CRL distribution points extension. The component will then make HTTP requests to each CRL endpoint to check the validity of the server's certificate. If the certificate has been revoked or any other issues are found during validation the component throws an exception.

When set to 0 (default), the CRL check will not be performed by the component. When set to 1, it will attempt to perform the CRL check, but it will continue without an error if the server's certificate does not support CRL. When set to 2, it will perform the CRL check and will throw an error if CRL is not supported.

This configuration setting is supported only in the Java, C#, and C++ editions. In the C++ edition, it is supported only on Windows operating systems.

SSLCheckOCSP: Whether to use OCSP to check the status of the server certificate.

This configuration setting specifies whether the component will use OCSP to check the validity of the server certificate. If set to 1 or 2, the component will first obtain the Online Certificate Status Protocol (OCSP) URL from the server certificate's OCSP extension. The component will then locate the issuing certificate and make an HTTP request to the OCSP endpoint to check the validity of the server's certificate. If the certificate has been revoked or any other issues are found during validation, the component throws an exception.

When set to 0 (default), the component will not perform an OCSP check. When set to 1, it will attempt to perform the OCSP check, but it will continue without an error if the server's certificate does not support OCSP. When set to 2, it will perform the OCSP check and will throw an error if OCSP is not supported.

This configuration setting is supported only in the Java, C#, and C++ editions. In the C++ edition, it is supported only on Windows operating systems.

SSLCipherStrength: The minimum cipher strength used for bulk encryption.

This minimum cipher strength is largely dependent on the security modules installed on the system. If the cipher strength specified is not supported, an error will be returned when connections are initiated.

Note: This configuration setting contains the minimum cipher strength requested from the security library. The actual cipher strength used for the connection is shown by the SSLStatus event.

Use this configuration setting with caution. Requesting a lower cipher strength than necessary could potentially cause serious security vulnerabilities in your application.

When the provider is OpenSSL, SSLCipherStrength is currently not supported. This functionality is instead made available through the OpenSSLCipherList configuration setting.

SSLClientCACerts: A newline separated list of CA certificates to use during SSL client certificate validation.

This configuration setting is only applicable to server components (e.g., TCPServer) see SSLServerCACerts for client components (e.g., TCPClient). This setting can be used to optionally specify one or more CA certificates to be used when verifying the client certificate that is presented by the client during the SSL handshake when SSLAuthenticateClients is enabled. When verifying the client's certificate, the certificates trusted by the system will be used as part of the verification process. If the client's CA certificates are not installed to the trusted system store, they may be specified here so they are included when performing the verification process. This configuration setting should be set only if the client's CA certificates are not already trusted on the system and cannot be installed to the trusted system store.

The value of this configuration setting is a newline-separated (CR/LF) list of certificates. For instance:

-----BEGIN CERTIFICATE-----
MIIEKzCCAxOgAwIBAgIRANTET4LIkxdH6P+CFIiHvTowDQYJKoZIhvcNAQELBQAw
... Intermediate Cert ...
eWHV5OW1K53o/atv59sOiW5K3crjFhsBOd5Q+cJJnU+SWinPKtANXMht+EDvYY2w
F0I1XhM+pKj7FjDr+XNj
-----END CERTIFICATE-----
\r \n
-----BEGIN CERTIFICATE-----
MIIEFjCCAv6gAwIBAgIQetu1SMxpnENAnnOz1P+PtTANBgkqhkiG9w0BAQUFADBp
... Root Cert ...
d8q23djXZbVYiIfE9ebr4g3152BlVCHZ2GyPdjhIuLeH21VbT/dyEHHA
-----END CERTIFICATE-----

SSLEnabledCipherSuites: The cipher suite to be used in an SSL negotiation.

This configuration setting enables the cipher suites to be used in SSL negotiation.

By default, the enabled cipher suites will include all available ciphers ("*").

The special value "*" means that the component will pick all of the supported cipher suites. If SSLEnabledCipherSuites is set to any other value, only the specified cipher suites will be considered.

Multiple cipher suites are separated by semicolons.

Example values when SSLProvider is set to Platform include the following: obj.config("SSLEnabledCipherSuites=*"); obj.config("SSLEnabledCipherSuites=CALG_AES_256"); obj.config("SSLEnabledCipherSuites=CALG_AES_256;CALG_3DES"); Possible values when SSLProvider is set to Platform include the following:

CALG_3DES
CALG_3DES_112
CALG_AES
CALG_AES_128
CALG_AES_192
CALG_AES_256
CALG_AGREEDKEY_ANY
CALG_CYLINK_MEK
CALG_DES
CALG_DESX
CALG_DH_EPHEM
CALG_DH_SF
CALG_DSS_SIGN
CALG_ECDH
CALG_ECDH_EPHEM
CALG_ECDSA
CALG_ECMQV
CALG_HASH_REPLACE_OWF
CALG_HUGHES_MD5
CALG_HMAC
CALG_KEA_KEYX
CALG_MAC
CALG_MD2
CALG_MD4
CALG_MD5
CALG_NO_SIGN
CALG_OID_INFO_CNG_ONLY
CALG_OID_INFO_PARAMETERS
CALG_PCT1_MASTER
CALG_RC2
CALG_RC4
CALG_RC5
CALG_RSA_KEYX
CALG_RSA_SIGN
CALG_SCHANNEL_ENC_KEY
CALG_SCHANNEL_MAC_KEY
CALG_SCHANNEL_MASTER_HASH
CALG_SEAL
CALG_SHA
CALG_SHA1
CALG_SHA_256
CALG_SHA_384
CALG_SHA_512
CALG_SKIPJACK
CALG_SSL2_MASTER
CALG_SSL3_MASTER
CALG_SSL3_SHAMD5
CALG_TEK
CALG_TLS1_MASTER
CALG_TLS1PRF

Example values when SSLProvider is set to Internalinclude the following:

obj.config("SSLEnabledCipherSuites=*");
obj.config("SSLEnabledCipherSuites=TLS_DHE_DSS_WITH_AES_128_CBC_SHA");
obj.config("SSLEnabledCipherSuites=TLS_DHE_DSS_WITH_AES_128_CBC_SHA;TLS_ECDH_RSA_WITH_AES_128_CBC_SHA");

Possible values when SSLProvider is set to Internal include the following:

TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384
TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
TLS_ECDH_ECDSA_WITH_AES_256_GCM_SHA384
TLS_RSA_WITH_AES_256_GCM_SHA384
TLS_RSA_WITH_AES_128_GCM_SHA256
TLS_ECDH_ECDSA_WITH_AES_128_GCM_SHA256
TLS_DHE_DSS_WITH_AES_256_GCM_SHA384
TLS_DHE_RSA_WITH_AES_256_GCM_SHA384
TLS_ECDH_RSA_WITH_AES_256_GCM_SHA384
TLS_ECDH_RSA_WITH_AES_128_GCM_SHA256
TLS_DHE_RSA_WITH_AES_128_GCM_SHA256
TLS_DHE_DSS_WITH_AES_128_GCM_SHA256
TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384
TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256
TLS_ECDH_ECDSA_WITH_AES_256_CBC_SHA384
TLS_DHE_DSS_WITH_AES_256_CBC_SHA256
TLS_RSA_WITH_AES_256_CBC_SHA256
TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384
TLS_ECDH_RSA_WITH_AES_256_CBC_SHA384
TLS_DHE_RSA_WITH_AES_256_CBC_SHA256
TLS_DHE_RSA_WITH_AES_128_CBC_SHA256
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256
TLS_RSA_WITH_AES_128_CBC_SHA256
TLS_ECDH_ECDSA_WITH_AES_128_CBC_SHA256
TLS_ECDH_RSA_WITH_AES_128_CBC_SHA256
TLS_DHE_DSS_WITH_AES_128_CBC_SHA256
TLS_RSA_WITH_AES_256_CBC_SHA
TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
TLS_ECDH_ECDSA_WITH_AES_256_CBC_SHA
TLS_DHE_RSA_WITH_AES_256_CBC_SHA
TLS_ECDH_RSA_WITH_AES_256_CBC_SHA
TLS_DHE_DSS_WITH_AES_256_CBC_SHA
TLS_RSA_WITH_AES_128_CBC_SHA
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
TLS_ECDH_ECDSA_WITH_AES_128_CBC_SHA
TLS_ECDH_RSA_WITH_AES_128_CBC_SHA
TLS_DHE_RSA_WITH_AES_128_CBC_SHA
TLS_DHE_DSS_WITH_AES_128_CBC_SHA
TLS_ECDHE_ECDSA_WITH_3DES_EDE_CBC_SHA
TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA
TLS_ECDH_ECDSA_WITH_3DES_EDE_CBC_SHA
TLS_ECDH_RSA_WITH_3DES_EDE_CBC_SHA
TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA
TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA
TLS_RSA_WITH_3DES_EDE_CBC_SHA
TLS_RSA_WITH_DES_CBC_SHA
TLS_DHE_RSA_WITH_DES_CBC_SHA
TLS_DHE_DSS_WITH_DES_CBC_SHA
TLS_RSA_WITH_RC4_128_MD5
TLS_RSA_WITH_RC4_128_SHA

When TLS 1.3 is negotiated (see SSLEnabledProtocols), only the following cipher suites are supported:

TLS_AES_256_GCM_SHA384
TLS_CHACHA20_POLY1305_SHA256
TLS_AES_128_GCM_SHA256

SSLEnabledCipherSuites is used together with SSLCipherStrength.

SSLEnabledProtocols: Used to enable/disable the supported security protocols.

This configuration setting is used to enable or disable the supported security protocols.

Not all supported protocols are enabled by default. The default value is 4032 for client components, and 3072 for server components. To specify a combination of enabled protocol versions set this config to the binary OR of one or more of the following values:


TLS1.3	12288 (Hex 3000)
TLS1.2	3072 (Hex C00) (Default - Client and Server)
TLS1.1	768 (Hex 300) (Default - Client)
TLS1	192 (Hex C0) (Default - Client)
SSL3	48 (Hex 30)
SSL2	12 (Hex 0C)

Note that only TLS 1.2 is enabled for server components that accept incoming connections. This adheres to industry standards to ensure a secure connection. Client components enable TLS 1.0, TLS 1.1, and TLS 1.2 by default and will negotiate the highest mutually supported version when connecting to a server, which should be TLS 1.2 in most cases.

SSLEnabledProtocols: Transport Layer Security (TLS) 1.3 Notes:

By default when TLS 1.3 is enabled, the component will use the internal TLS implementation when the SSLProvider is set to Automatic for all editions.

In editions that are designed to run on Windows, SSLProvider can be set to Platform to use the platform implementation instead of the internal implementation. When configured in this manner, please note that the platform provider is supported only on Windows 11/Windows Server 2022 and up. The default internal provider is available on all platforms and is not restricted to any specific OS version.

If set to 1 (Platform provider), please be aware of the following notes:

The platform provider is available only on Windows 11/Windows Server 2022 and up.
SSLEnabledCipherSuites and other similar SSL configuration settings are not supported.
If SSLEnabledProtocols includes both TLS 1.3 and TLS 1.2, these restrictions are still applicable even if TLS 1.2 is negotiated. Enabling TLS 1.3 with the platform provider changes the implementation used for all TLS versions.

SSLEnabledProtocols: SSL2 and SSL3 Notes:

SSL 2.0 and 3.0 are not supported by the component when the SSLProvider is set to internal. To use SSL 2.0 or SSL 3.0, the platform security API must have the protocols enabled and SSLProvider needs to be set to platform.

SSLEnableRenegotiation: Whether the renegotiation_info SSL extension is supported.

This configuration setting specifies whether the renegotiation_info SSL extension will be used in the request when using the internal security API. This configuration setting is false by default, but it can be set to true to enable the extension.

This configuration setting is applicable only when SSLProvider is set to Internal.

SSLIncludeCertChain: Whether the entire certificate chain is included in the SSLServerAuthentication event.

This configuration setting specifies whether the Encoded parameter of the SSLServerAuthentication event contains the full certificate chain. By default this value is False and only the leaf certificate will be present in the Encoded parameter of the SSLServerAuthentication event.

If set to True, all certificates returned by the server will be present in the Encoded parameter of the SSLServerAuthentication event. This includes the leaf certificate, any intermediate certificate, and the root certificate.

Note: When SSLProvider is set to Internal this value is automatically set to true. This is needed for proper validation when using the internal provider.

SSLKeyLogFile: The location of a file where per-session secrets are written for debugging purposes.

This configuration setting optionally specifies the full path to a file on disk where per-session secrets are stored for debugging purposes.

When set, the component will save the session secrets in the same format as the SSLKEYLOGFILE environment variable functionality used by most major browsers and tools, such as Chrome, Firefox, and cURL. This file can then be used in tools such as Wireshark to decrypt TLS traffic for debugging purposes. When writing to this file, the component will only append, it will not overwrite previous values.

Note: This configuration setting is applicable only when SSLProvider is set to Internal.

SSLNegotiatedCipher: Returns the negotiated cipher suite.

This configuration setting returns the cipher suite negotiated during the SSL handshake.

Note: For server components (e.g., TCPServer), this is a per-connection configuration setting accessed by passing the ConnectionId. For example: server.Config("SSLNegotiatedCipher[connId]");

SSLNegotiatedCipherStrength: Returns the negotiated cipher suite strength.

This configuration setting returns the strength of the cipher suite negotiated during the SSL handshake.

Note: For server components (e.g., TCPServer), this is a per-connection configuration setting accessed by passing the ConnectionId. For example: server.Config("SSLNegotiatedCipherStrength[connId]");

SSLNegotiatedCipherSuite: Returns the negotiated cipher suite.

This configuration setting returns the cipher suite negotiated during the SSL handshake represented as a single string.

SSLNegotiatedKeyExchange: Returns the negotiated key exchange algorithm.

This configuration setting returns the key exchange algorithm negotiated during the SSL handshake.

SSLNegotiatedKeyExchangeStrength: Returns the negotiated key exchange algorithm strength.

This configuration setting returns the strength of the key exchange algorithm negotiated during the SSL handshake.

SSLNegotiatedVersion: Returns the negotiated protocol version.

This configuration setting returns the protocol version negotiated during the SSL handshake.

Note: For server components (e.g., TCPServer), this is a per-connection configuration setting accessed by passing the ConnectionId. For example: server.Config("SSLNegotiatedVersion[connId]");

SSLSecurityFlags: Flags that control certificate verification.

The following flags are defined (specified in hexadecimal notation). They can be ORed together to exclude multiple conditions:


0x00000001	Ignore time validity status of certificate.
0x00000002	Ignore time validity status of CTL.
0x00000004	Ignore non-nested certificate times.
0x00000010	Allow unknown certificate authority.
0x00000020	Ignore wrong certificate usage.
0x00000100	Ignore unknown certificate revocation status.
0x00000200	Ignore unknown CTL signer revocation status.
0x00000400	Ignore unknown certificate authority revocation status.
0x00000800	Ignore unknown root revocation status.
0x00008000	Allow test root certificate.
0x00004000	Trust test root certificate.
0x80000000	Ignore non-matching CN (certificate CN non-matching server name).

This functionality is currently not available in Java or when the provider is OpenSSL.

SSLServerCACerts: A newline separated list of CA certificates to use during SSL server certificate validation.

This configuration setting is only used by client components (e.g., TCPClient) see SSLClientCACerts for server components (e.g., TCPServer). This configuration setting can be used to optionally specify one or more CA certificates to be used when connecting to the server and verifying the server certificate. When verifying the server's certificate, the certificates trusted by the system will be used as part of the verification process. If the server's CA certificates are not installed to the trusted system store, they may be specified here so they are included when performing the verification process. This configuration setting should be set only if the server's CA certificates are not already trusted on the system and cannot be installed to the trusted system store.

The value of this configuration setting is a newline-separated (CR/LF) list of certificates. For instance:

-----BEGIN CERTIFICATE-----
MIIEKzCCAxOgAwIBAgIRANTET4LIkxdH6P+CFIiHvTowDQYJKoZIhvcNAQELBQAw
... Intermediate Cert...
eWHV5OW1K53o/atv59sOiW5K3crjFhsBOd5Q+cJJnU+SWinPKtANXMht+EDvYY2w
F0I1XhM+pKj7FjDr+XNj
-----END CERTIFICATE-----
\r \n
-----BEGIN CERTIFICATE-----
MIIEFjCCAv6gAwIBAgIQetu1SMxpnENAnnOz1P+PtTANBgkqhkiG9w0BAQUFADBp
... Root Cert...
d8q23djXZbVYiIfE9ebr4g3152BlVCHZ2GyPdjhIuLeH21VbT/dyEHHA
-----END CERTIFICATE-----

TLS12SignatureAlgorithms: Defines the allowed TLS 1.2 signature algorithms when SSLProvider is set to Internal.

This configuration setting specifies the allowed server certificate signature algorithms when SSLProvider is set to Internal and SSLEnabledProtocols is set to allow TLS 1.2.

When specified the component will verify that the server certificate signature algorithm is among the values specified in this configuration setting. If the server certificate signature algorithm is unsupported, the component throws an exception.

The format of this value is a comma-separated list of hash-signature combinations. For instance: component.SSLProvider = TCPClientSSLProviders.sslpInternal; component.Config("SSLEnabledProtocols=3072"); //TLS 1.2 component.Config("TLS12SignatureAlgorithms=sha256-rsa,sha256-dsa,sha1-rsa,sha1-dsa"); The default value for this configuration setting is sha512-ecdsa,sha512-rsa,sha512-dsa,sha384-ecdsa,sha384-rsa,sha384-dsa,sha256-ecdsa,sha256-rsa,sha256-dsa,sha224-ecdsa,sha224-rsa,sha224-dsa,sha1-ecdsa,sha1-rsa,sha1-dsa.

To not restrict the server's certificate signature algorithm, specify an empty string as the value for this configuration setting, which will cause the signature_algorithms TLS 1.2 extension to not be sent.

TLS12SupportedGroups: The supported groups for ECC.

This configuration setting specifies a comma-separated list of named groups used in TLS 1.2 for ECC.

The default value is ecdhe_secp256r1,ecdhe_secp384r1,ecdhe_secp521r1.

When using TLS 1.2 and SSLProvider is set to Internal, the values refer to the supported groups for ECC. The following values are supported:

"ecdhe_secp256r1" (default)
"ecdhe_secp384r1" (default)
"ecdhe_secp521r1" (default)

TLS13KeyShareGroups: The groups for which to pregenerate key shares.

This configuration setting specifies a comma-separated list of named groups used in TLS 1.3 for key exchange. The groups specified here will have key share data pregenerated locally before establishing a connection. This can prevent an additional roundtrip during the handshake if the group is supported by the server.

The default value is set to balance common supported groups and the computational resources required to generate key shares. As a result, only some groups are included by default in this configuration setting.

Note: All supported groups can always be used during the handshake even if not listed here, but if a group is used that is not present in this list, it will incur an additional roundtrip and time to generate the key share for that group.

In most cases, this configuration setting does not need to be modified. This should be modified only if there is a specific reason to do so.

The default value is ecdhe_x25519,ecdhe_secp256r1,ecdhe_secp384r1,ffdhe_2048,ffdhe_3072

The values are ordered from most preferred to least preferred. The following values are supported:

"ecdhe_x25519" (default)
"ecdhe_x448"
"ecdhe_secp256r1" (default)
"ecdhe_secp384r1" (default)
"ecdhe_secp521r1"
"ffdhe_2048" (default)
"ffdhe_3072" (default)
"ffdhe_4096"
"ffdhe_6144"
"ffdhe_8192"

TLS13SignatureAlgorithms: The allowed certificate signature algorithms.

This configuration setting holds a comma-separated list of allowed signature algorithms. Possible values include the following:

"ed25519" (default)
"ed448" (default)
"ecdsa_secp256r1_sha256" (default)
"ecdsa_secp384r1_sha384" (default)
"ecdsa_secp521r1_sha512" (default)
"rsa_pkcs1_sha256" (default)
"rsa_pkcs1_sha384" (default)
"rsa_pkcs1_sha512" (default)
"rsa_pss_sha256" (default)
"rsa_pss_sha384" (default)
"rsa_pss_sha512" (default)

The default value is rsa_pss_sha256,rsa_pss_sha384,rsa_pss_sha512,rsa_pkcs1_sha256,rsa_pkcs1_sha384,rsa_pkcs1_sha512,ecdsa_secp256r1_sha256,ecdsa_secp384r1_sha384,ecdsa_secp521r1_sha512,ed25519,ed448. This configuration setting is applicable only when SSLEnabledProtocols includes TLS 1.3.

TLS13SupportedGroups: The supported groups for (EC)DHE key exchange.

This configuration setting specifies a comma-separated list of named groups used in TLS 1.3 for key exchange. This configuration setting should be modified only if there is a specific reason to do so.

The default value is ecdhe_x25519,ecdhe_x448,ecdhe_secp256r1,ecdhe_secp384r1,ecdhe_secp521r1,ffdhe_2048,ffdhe_3072,ffdhe_4096,ffdhe_6144,ffdhe_8192

The values are ordered from most preferred to least preferred. The following values are supported:

"ecdhe_x25519" (default)
"ecdhe_x448" (default)
"ecdhe_secp256r1" (default)
"ecdhe_secp384r1" (default)
"ecdhe_secp521r1" (default)
"ffdhe_2048" (default)
"ffdhe_3072" (default)
"ffdhe_4096" (default)
"ffdhe_6144" (default)
"ffdhe_8192" (default)

Socket Config Settings

AbsoluteTimeout: Determines whether timeouts are inactivity timeouts or absolute timeouts.

If AbsoluteTimeout is set to True, any method that does not complete within Timeout seconds will be aborted. By default, AbsoluteTimeout is False, and the timeout is an inactivity timeout.

Note: This option is not valid for User Datagram Protocol (UDP) ports.

FirewallData: Used to send extra data to the firewall.

When the firewall is a tunneling proxy, use this property to send custom (additional) headers to the firewall (e.g., headers for custom authentication schemes).

InBufferSize: The size in bytes of the incoming queue of the socket.

This is the size of an internal queue in the Transmission Control Protocol (TCP)/IP stack. You can increase or decrease its size depending on the amount of data that you will be receiving. In some cases, increasing the value of the InBufferSize setting can provide significant improvements in performance.

Some TCP/IP implementations do not support variable buffer sizes. If that is the case, when the component is activated the InBufferSize reverts to its defined size. The same happens if you attempt to make it too large or too small.

OutBufferSize: The size in bytes of the outgoing queue of the socket.

This is the size of an internal queue in the TCP/IP stack. You can increase or decrease its size depending on the amount of data that you will be sending. In some cases, increasing the value of the OutBufferSize setting can provide significant improvements in performance.

Some TCP/IP implementations do not support variable buffer sizes. If that is the case, when the component is activated the OutBufferSize reverts to its defined size. The same happens if you attempt to make it too large or too small.

Base Config Settings

BuildInfo: Information about the product's build.

When queried, this setting will return a string containing information about the product's build.

GUIAvailable: Whether or not a message loop is available for processing events.

In a GUI-based application, long-running blocking operations may cause the application to stop responding to input until the operation returns. The component will attempt to discover whether or not the application has a message loop and, if one is discovered, it will process events in that message loop during any such blocking operation.

In some non-GUI applications, an invalid message loop may be discovered that will result in errant behavior. In these cases, setting GUIAvailable to false will ensure that the component does not attempt to process external events.

LicenseInfo: Information about the current license.

When queried, this setting will return a string containing information about the license this instance of a component is using. It will return the following information:

Product: The product the license is for.
Product Key: The key the license was generated from.
License Source: Where the license was found (e.g., RuntimeLicense, License File).
License Type: The type of license installed (e.g., Royalty Free, Single Server).
Last Valid Build: The last valid build number for which the license will work.

MaskSensitiveData: Whether sensitive data is masked in log messages.

In certain circumstances it may be beneficial to mask sensitive data, like passwords, in log messages. Set this to true to mask sensitive data. The default is true.

This setting only works on these components: AS3Receiver, AS3Sender, Atom, Client(3DS), FTP, FTPServer, IMAP, OFTPClient, SSHClient, SCP, Server(3DS), Sexec, SFTP, SFTPServer, SSHServer, TCPClient, TCPServer.

UseFIPSCompliantAPI: Tells the component whether or not to use FIPS certified APIs.

When set to true, the component will utilize the underlying operating system's certified APIs. Java editions, regardless of OS, utilize Bouncy Castle Federal Information Processing Standards (FIPS), while all other Windows editions make use of Microsoft security libraries.

FIPS mode can be enabled by setting the UseFIPSCompliantAPI configuration setting to true. This is a static setting that applies to all instances of all components of the toolkit within the process. It is recommended to enable or disable this setting once before the component has been used to establish a connection. Enabling FIPS while an instance of the component is active and connected may result in unexpected behavior.

For more details, please see the FIPS 140-2 Compliance article.

Note: This setting is applicable only on Windows.

Note: Enabling FIPS compliance requires a special license; please contact sales@nsoftware.com for details.

UseInternalSecurityAPI: Whether or not to use the system security libraries or an internal implementation.

When set to false, the component will use the system security libraries by default to perform cryptographic functions where applicable. In this case, calls to unmanaged code will be made. In certain environments, this is not desirable. To use a completely managed security implementation, set this setting to true.

Setting this configuration setting to true tells the component to use the internal implementation instead of using the system security libraries.

On Windows, this setting is set to false by default. On Linux/macOS, this setting is set to true by default.

If using the .NET Standard Library, this setting will be true on all platforms. The .NET Standard library does not support using the system security libraries.

Note: This setting is static. The value set is applicable to all components used in the application.

When this value is set, the product's system dynamic link library (DLL) is no longer required as a reference, as all unmanaged code is stored in that file.

Trappable Errors (SMTP Component)

SMTP Errors

118	Firewall Error. Error message contains detailed description.
161	SMTP protocol error. Description contains the server reply.
162	Error communicating with server. Error text is attached.
163	Please specify a MailServer.
164	Please specify a sender (From).
165	Please specify a recipient.
166	Busy executing current method.
301	Operation interrupted.
302	Cannot open AttachedFile.

The component may also return one of the following error codes, which are inherited from other components.

TCPClient Errors

100	You cannot change the RemotePort at this time. A connection is in progress.
101	You cannot change the RemoteHost (Server) at this time. A connection is in progress.
102	The RemoteHost address is invalid (0.0.0.0).
104	Already connected. If you want to reconnect, close the current connection first.
106	You cannot change the LocalPort at this time. A connection is in progress.
107	You cannot change the LocalHost at this time. A connection is in progress.
112	You cannot change MaxLineLength at this time. A connection is in progress.
116	RemotePort cannot be zero. Please specify a valid service port number.
117	You cannot change the UseConnection option while the component is active.
135	Operation would block.
201	Timeout.
211	Action impossible in control's present state.
212	Action impossible while not connected.
213	Action impossible while listening.
301	Timeout.
303	Could not open file.
434	Unable to convert string to selected CodePage.
1105	Already connecting. If you want to reconnect, close the current connection first.
1117	You need to connect first.
1119	You cannot change the LocalHost at this time. A connection is in progress.
1120	Connection dropped by remote host.

TCP/IP Errors

10004	[10004] Interrupted system call.
10009	[10009] Bad file number.
10013	[10013] Access denied.
10014	[10014] Bad address.
10022	[10022] Invalid argument.
10024	[10024] Too many open files.
10035	[10035] Operation would block.
10036	[10036] Operation now in progress.
10037	[10037] Operation already in progress.
10038	[10038] Socket operation on nonsocket.
10039	[10039] Destination address required.
10040	[10040] Message is too long.
10041	[10041] Protocol wrong type for socket.
10042	[10042] Bad protocol option.
10043	[10043] Protocol is not supported.
10044	[10044] Socket type is not supported.
10045	[10045] Operation is not supported on socket.
10046	[10046] Protocol family is not supported.
10047	[10047] Address family is not supported by protocol family.
10048	[10048] Address already in use.
10049	[10049] Cannot assign requested address.
10050	[10050] Network is down.
10051	[10051] Network is unreachable.
10052	[10052] Net dropped connection or reset.
10053	[10053] Software caused connection abort.
10054	[10054] Connection reset by peer.
10055	[10055] No buffer space available.
10056	[10056] Socket is already connected.
10057	[10057] Socket is not connected.
10058	[10058] Cannot send after socket shutdown.
10059	[10059] Too many references, cannot splice.
10060	[10060] Connection timed out.
10061	[10061] Connection refused.
10062	[10062] Too many levels of symbolic links.
10063	[10063] File name is too long.
10064	[10064] Host is down.
10065	[10065] No route to host.
10066	[10066] Directory is not empty
10067	[10067] Too many processes.
10068	[10068] Too many users.
10069	[10069] Disc Quota Exceeded.
10070	[10070] Stale NFS file handle.
10071	[10071] Too many levels of remote in path.
10091	[10091] Network subsystem is unavailable.
10092	[10092] WINSOCK DLL Version out of range.
10093	[10093] Winsock is not loaded yet.
11001	[11001] Host not found.
11002	[11002] Nonauthoritative 'Host not found' (try again or check DNS setup).
11003	[11003] Nonrecoverable errors: FORMERR, REFUSED, NOTIMP.
11004	[11004] Valid name, no data record (check DNS setup).