DTLSServer Control

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The DTLSServer control provides server-side functionality for secure UDP communication utilizing the Datagram Transport Layer Security (DTLS) protocol.

Syntax

DTLSServer

Remarks

The DTLSServer control functions as a server that facilitates incoming DTLS connections and offers a convenient means of transmitting and receiving datagrams over the established, secure connections.

Getting Started

First, a valid certificate must be selected before the server can start listening for incoming connections. The certificate can be specified via the SSLCert. Note the certificate must contain a private key.

After doing so, calling StartListening will cause the control to start listening for incoming connections. The control will listen on the interface defined by LocalHost and LocalPort, if specified. Otherwise, these values will be set by the control. If applicable, these values must be set before calling StartListening. For example:

//dtlsserver.LocalHost = "some_ip_address"; //dtlsserver.LocalPort = 1234; dtlsserver.SSLCert = new Certificate("/path/to/cert.pfx", CertStoreTypes.cstPFXFile, "cert_password", "cert_subject"); dtlsserver.StartListening(); Console.WriteLine("Listening on: " + dtlsserver.LocalHost + ":" + dtlsserver.LocalPort); while (dtlsserver.Listening) { dtlsserver.DoEvents(); }

Handling Incoming Connections

Once successfully listening, the control can now accept (or reject) incoming connections. The first indicator of an incoming connection will be through the ConnectionRequest event. Here, the connection's originating address and port can be queried. By default, the control will accept all incoming connections, but this behavior can be overridden within this event.

Assuming the connection is accepted, the DTLS handshake will proceed. Relevant handshake details will be reported by the SSLStatus event. By default, the client is not required to present a certificate to the server. To force this, the SSLAuthenticateClients property can be enabled. When enabled, the client's presented certificate will be available within the SSLClientAuthentication event, where the server can again choose to accept (or reject) incoming connections.

Once the connection is complete (or fails), the Connected event will fire. Note that this event will fire if a connection succeeds or fails. If successful, the event will fire with a StatusCode of 0. If this value is non-zero, it indicates the connection was unsuccessful. The Description parameter will contain relevant details.

After a successful connection, relevant connection-specific details will be available within the Connection* properties. Each connection will be assigned a unique ConnectionId, which can be acquired for a given connection within the Connected event. For example:

dtlsserver.OnConnected += (o, e) => { if (e.StatusCode == 0) { Console.WriteLine("Successful connection from " + e.SourceAddr + ":" + e.SourcePort); Console.WriteLine("ConnectionId: " + e.ConnectionId); } else { Console.WriteLine("Connection failed from " + e.SourceAddr + ":" + e.SourcePort); Console.WriteLine("Error code: " + e.StatusCode); Console.WriteLine("Error description: " + e.Description); } }; dtlsserver.OnSSLClientAuthentication += (o, e) => { if (e.Accept) return; Console.Write("Client provided the following certificate:\nIssuer: " + e.CertIssuer + "\nSubject: " + e.CertSubject + "\n"); Console.Write("The following problems have been determined for this certificate: " + e.Status + "\n"); Console.Write("Would you like to accept anyways? [y/n] "); if (Console.Read() == 'y') e.Accept = true; }; dtlsserver.SSLCert = new Certificate("/path/to/cert.pfx", CertStoreTypes.cstPFXFile, "cert_password", "cert_subject"); dtlsserver.AuthenticateClients = true; dtlsserver.StartListening(); Console.WriteLine("Listening on: " + dtlsserver.LocalHost + ":" + dtlsserver.LocalPort); while (dtlsserver.Listening) { dtlsserver.DoEvents(); }

Sending and Receiving Data

The control can send data to individual connections, specified by the ConnectionId parameter, via the SendBytes and SendText methods.

While a connection is active, incoming data from a connection will be available within the DataIn event. Note that this event is non-reentrant, and it is recommended to offload time-consuming operations to ensure the best performance.

If required, the PauseData method can be called, disabling the reception of incoming data from a particular connection. Data reception can later be enabled via the ProcessData method. Note that if this reception is disabled for a connection, the connection may continue sending data, which will remain unprocessed by the control. In this case, the underlying socket buffer may be filled. This can result in possible data loss originating from this connection. Please use these methods with caution.

The complete process may look like the following:

dtlsserver.OnDataIn += (o, e) => { Console.WriteLine("Packet received from: " + e.ConnectionId); Console.WriteLine("Packet: " + e.Datagram); }; dtlsserver.SSLCert = new Certificate("/path/to/cert.pfx", CertStoreTypes.cstPFXFile, "cert_password", "cert_subject"); dtlsserver.StartListening(); Console.WriteLine("Listening on: " + dtlsserver.LocalHost + ":" + dtlsserver.LocalPort); ... ... ... // Broadcast data foreach (DTLSConnection c in dtlsserver.Connections.Values) { dtlsserver.SendText(c.ConnectionId, "Hello world!"); }

Removing Connections

To remove a connection, Disconnect must be called with the corresponding ConnectionId. In order to remove inactive connections, the DefaultIdleTimeout property can be set accordingly. By default, this property is set to 0, and idle connections are not removed automatically. When this property is set to a positive value, this will automatically remove connections that are idle for a specified amount of time.

Note: For DefaultIdleTimeout to work as intended, DoEvents must be called frequently in both console and form-based applications (e.g., using a loop or timer).

Finally, once a connection ends, Disconnected will fire. In the case a connection ends and an error is encountered, the StatusCode and Description parameters will contain relevant details regarding the error. The connection will be removed from the Connection* properties. For example:

dtlsserver.OnDisconnected += (o, e) => { if (e.StatusCode == 0) { Console.WriteLine("Connection removed: " + e.ConnectionId); } else { Console.WriteLine("Connection removed: " + e.ConnectionId); Console.WriteLine("Error code: " + e.StatusCode); Console.WriteLine("Error description: " + e.Description); } }; dtlsserver.DefaultIdleTimeout = 60; // Remove connections inactive for 60 seconds dtlsserver.StartListening(); Console.WriteLine("Listening on: " + dtlsserver.LocalHost + ":" + dtlsserver.LocalPort); while (dtlsserver.Listening) { dtlsserver.DoEvents(); }

Additional Information

To support DefaultIdleTimeout and KeepAlive functionality, it is important to note that DoEvents must be called regularly in both console and form-based applications.

For DefaultIdleTimeout, DoEvents must be called frequently to ensure that idle connections are handled and removed in a timely manner. For KeepAlive, DoEvents must be called frequently to ensure the control sends keep-alive (or Heartbeat) packets to existing connections in a timely manner.

In form-based applications, this does not apply if DefaultIdleTimeout is set to 0 and KeepAlive is False.

Property List

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

Method List

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

Event List

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

Config Settings

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

ConnectionCount Property (DTLSServer Control)

The number of records in the Connection arrays.

Syntax

dtlsservercontrol.ConnectionCount[=integer]

Default Value

0

Remarks

This property controls the size of the following arrays:

• ConnectionConnectionId
• ConnectionLocalHost
• ConnectionLocalPort
• ConnectionRemoteHost
• ConnectionRemotePort

The array indices start at 0 and end at ConnectionCount - 1.

This property is not available at design time.

Data Type

Integer

ConnectionConnectionId Property (DTLSServer Control)

This property contains an identifier generated by the control to identify each connection.

Syntax

dtlsservercontrol.ConnectionConnectionId(ConnectionId)

Default Value

0

Remarks

This property contains an identifier generated by the control to identify each connection. This identifier is unique to this connection.

The ConnectionId parameter specifies the index of the item in the array. The size of the array is controlled by the ConnectionCount property.

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

Data Type

Integer

ConnectionLocalHost Property (DTLSServer Control)

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

Syntax

dtlsservercontrol.ConnectionLocalHost(ConnectionId)

Default Value

""

Remarks

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

The ConnectionId parameter specifies the index of the item in the array. The size of the array is controlled by the ConnectionCount property.

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

Data Type

String

ConnectionLocalPort Property (DTLSServer Control)

This property indicates the UDP port on the local host or user-assigned IP interface through which connections are initiated or accepted.

Syntax

dtlsservercontrol.ConnectionLocalPort(ConnectionId)

Default Value

0

Remarks

This property indicates the UDP port on the local host or user-assigned IP interface through which connections are initiated or accepted.

The ConnectionId parameter specifies the index of the item in the array. The size of the array is controlled by the ConnectionCount property.

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

Data Type

Integer

ConnectionRemoteHost Property (DTLSServer Control)

This property indicates the IP address of the remote host through which the connection is coming.

Syntax

dtlsservercontrol.ConnectionRemoteHost(ConnectionId)

Default Value

""

Remarks

This property indicates the IP address of the remote host through which the connection is coming.

The connection must be valid or an error will be fired.

If the control 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.

The ConnectionId parameter specifies the index of the item in the array. The size of the array is controlled by the ConnectionCount property.

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

Data Type

String

ConnectionRemotePort Property (DTLSServer Control)

This property indicates the UDP port on the remote host through which the connection is coming.

Syntax

dtlsservercontrol.ConnectionRemotePort(ConnectionId)

Default Value

0

Remarks

This property indicates the UDP port on the remote host through which the connection is coming.

The connection must be valid or an error will be fired.

The ConnectionId parameter specifies the index of the item in the array. The size of the array is controlled by the ConnectionCount property.

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

Data Type

Integer

DefaultIdleTimeout Property (DTLSServer Control)

This property includes the default idle timeout for inactive clients.

Syntax

dtlsservercontrol.DefaultIdleTimeout[=integer]

Default Value

0

Remarks

This property specifies the idle timeout (in seconds) for clients. When set to a positive value, the control will disconnect idle clients after the specified timeout.

This applies only to clients that have not sent or received data within DefaultIdleTimeout seconds.

If set to 0 (default), no idle timeout is applied.

Note: DoEvents must be called for the control to check existing connections.

Data Type

Integer

KeepAlive Property (DTLSServer Control)

When True, keep-alive functionality is enabled via the DTLS Heartbeat Extension.

Syntax

dtlsservercontrol.KeepAlive[=boolean]

Default Value

False

Remarks

This property enables keep-alive functionality for established connections via the DTLS Heartbeat Extension (RFC 6520). Enabling this option can prevent long connections from timing out in case of inactivity.

Note: For this functionality to work as intended, DoEvents must be called frequently in both console and form-based applications (e.g., using a loop or timer).

Additionally, DTLS server implementations are not required to support Heartbeats.

Data Type

Boolean

Listening Property (DTLSServer Control)

This property indicates whether the control is listening for incoming connections on LocalPort.

Syntax

dtlsservercontrol.Listening

Default Value

False

Remarks

This property indicates whether the control is listening for connections on the port specified by the LocalPort property. Use the StartListening and StopListening methods to control whether the control is listening.

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

Data Type

Boolean

LocalHost Property (DTLSServer Control)

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

Syntax

dtlsservercontrol.LocalHost[=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 control initiate connections (or accept in the case of server controls) 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 control 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.

Data Type

String

LocalPort Property (DTLSServer Control)

This property includes the Transmission Control Protocol (TCP) port in the local host where the control listens.

Syntax

dtlsservercontrol.LocalPort[=integer]

Default Value

0

Remarks

This property must be set before the control can start listening. If its value is 0, then the TCP/IP subsystem picks a port number at random. The port number can be found by checking the value of this property after the control is listening (i.e., after successfully assigning True to the Listening property).

The service port is not shared among servers so two controls cannot be listening on the same port at the same time.

Data Type

Integer

SSLAuthenticateClients Property (DTLSServer Control)

If set to True, the server asks the client(s) for a certificate.

Syntax

dtlsservercontrol.SSLAuthenticateClients[=boolean]

Default Value

False

Remarks

This property is used in conjunction with the SSLClientAuthentication event. Please refer to the documentation of the SSLClientAuthentication event for details.

Data Type

Boolean

SSLCertEffectiveDate Property (DTLSServer Control)

The date on which this certificate becomes valid.

Syntax

dtlsservercontrol.SSLCertEffectiveDate

Default Value

""

Remarks

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.

This property is read-only.

Data Type

String

SSLCertExpirationDate Property (DTLSServer Control)

The date on which the certificate expires.

Syntax

dtlsservercontrol.SSLCertExpirationDate

Default Value

""

Remarks

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.

This property is read-only.

Data Type

String

SSLCertExtendedKeyUsage Property (DTLSServer Control)

A comma-delimited list of extended key usage identifiers.

Syntax

dtlsservercontrol.SSLCertExtendedKeyUsage

Default Value

""

Remarks

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

This property is read-only.

Data Type

String

SSLCertFingerprint Property (DTLSServer Control)

The hex-encoded, 16-byte MD5 fingerprint of the certificate.

Syntax

dtlsservercontrol.SSLCertFingerprint

Default Value

""

Remarks

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

This property is read-only.

Data Type

String

SSLCertFingerprintSHA1 Property (DTLSServer Control)

The hex-encoded, 20-byte SHA-1 fingerprint of the certificate.

Syntax

dtlsservercontrol.SSLCertFingerprintSHA1

Default Value

""

Remarks

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

This property is read-only.

Data Type

String

SSLCertFingerprintSHA256 Property (DTLSServer Control)

The hex-encoded, 32-byte SHA-256 fingerprint of the certificate.

Syntax

dtlsservercontrol.SSLCertFingerprintSHA256

Default Value

""

Remarks

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

This property is read-only.

Data Type

String

SSLCertIssuer Property (DTLSServer Control)

The issuer of the certificate.

Syntax

dtlsservercontrol.SSLCertIssuer

Default Value

""

Remarks

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

This property is read-only.

Data Type

String

SSLCertPrivateKey Property (DTLSServer Control)

The private key of the certificate (if available).

Syntax

dtlsservercontrol.SSLCertPrivateKey

Default Value

""

Remarks

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

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

This property is read-only.

Data Type

String

SSLCertPrivateKeyAvailable Property (DTLSServer Control)

Whether a PrivateKey is available for the selected certificate.

Syntax

dtlsservercontrol.SSLCertPrivateKeyAvailable

Default Value

False

Remarks

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

This property is read-only.

Data Type

Boolean

SSLCertPrivateKeyContainer Property (DTLSServer Control)

The name of the PrivateKey container for the certificate (if available).

Syntax

dtlsservercontrol.SSLCertPrivateKeyContainer

Default Value

""

Remarks

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

This property is read-only.

Data Type

String

SSLCertPublicKey Property (DTLSServer Control)

The public key of the certificate.

Syntax

dtlsservercontrol.SSLCertPublicKey

Default Value

""

Remarks

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

This property is read-only.

Data Type

String

SSLCertPublicKeyAlgorithm Property (DTLSServer Control)

The textual description of the certificate's public key algorithm.

Syntax

dtlsservercontrol.SSLCertPublicKeyAlgorithm

Default Value

""

Remarks

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.

This property is read-only.

Data Type

String

SSLCertPublicKeyLength Property (DTLSServer Control)

The length of the certificate's public key (in bits).

Syntax

dtlsservercontrol.SSLCertPublicKeyLength

Default Value

0

Remarks

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

This property is read-only.

Data Type

Integer

SSLCertSerialNumber Property (DTLSServer Control)

The serial number of the certificate encoded as a string.

Syntax

dtlsservercontrol.SSLCertSerialNumber

Default Value

""

Remarks

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.

This property is read-only.

Data Type

String

SSLCertSignatureAlgorithm Property (DTLSServer Control)

The text description of the certificate's signature algorithm.

Syntax

dtlsservercontrol.SSLCertSignatureAlgorithm

Default Value

""

Remarks

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.

This property is read-only.

Data Type

String

SSLCertStore Property (DTLSServer Control)

The name of the certificate store for the client certificate.

Syntax

dtlsservercontrol.SSLCertStore[=string]

Default Value

"MY"

Remarks

The name of the certificate store for the client certificate.

The SSLCertStoreType property denotes the type of the certificate store specified by SSLCertStore. If the store is password-protected, specify the password in SSLCertStorePassword.

SSLCertStore is used in conjunction with the SSLCertSubject property to specify client certificates. If SSLCertStore has a value, and SSLCertSubject or SSLCertEncoded is set, a search for a certificate is initiated. Please see the SSLCertSubject property for details.

Designations of certificate stores are platform dependent.

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

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).

To read or write binary data to the property, a Variant (Byte Array) version is provided in .SSLCertStoreB.

Data Type

Binary String

SSLCertStorePassword Property (DTLSServer Control)

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

Syntax

dtlsservercontrol.SSLCertStorePassword[=string]

Default Value

""

Remarks

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

Data Type

String

SSLCertStoreType Property (DTLSServer Control)

The type of certificate store for this certificate.

Syntax

dtlsservercontrol.SSLCertStoreType[=integer]

Possible Values

cstUser(0), 
cstMachine(1), 
cstPFXFile(2), 
cstPFXBlob(3), 
cstJKSFile(4), 
cstJKSBlob(5), 
cstPEMKeyFile(6), 
cstPEMKeyBlob(7), 
cstPublicKeyFile(8), 
cstPublicKeyBlob(9), 
cstSSHPublicKeyBlob(10), 
cstP7BFile(11), 
cstP7BBlob(12), 
cstSSHPublicKeyFile(13), 
cstPPKFile(14), 
cstPPKBlob(15), 
cstXMLFile(16), 
cstXMLBlob(17), 
cstJWKFile(18), 
cstJWKBlob(19), 
cstSecurityKey(20), 
cstBCFKSFile(21), 
cstBCFKSBlob(22), 
cstPKCS11(23), 
cstAuto(99)

Default Value

0

Remarks

The type of certificate store for this certificate.

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

Data Type

Integer

SSLCertSubjectAltNames Property (DTLSServer Control)

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

Syntax

dtlsservercontrol.SSLCertSubjectAltNames

Default Value

""

Remarks

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

This property is read-only.

Data Type

String

SSLCertThumbprintMD5 Property (DTLSServer Control)

The MD5 hash of the certificate.

Syntax

dtlsservercontrol.SSLCertThumbprintMD5

Default Value

""

Remarks

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.

This property is read-only.

Data Type

String

SSLCertThumbprintSHA1 Property (DTLSServer Control)

The SHA-1 hash of the certificate.

Syntax

dtlsservercontrol.SSLCertThumbprintSHA1

Default Value

""

Remarks

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.

This property is read-only.

Data Type

String

SSLCertThumbprintSHA256 Property (DTLSServer Control)

The SHA-256 hash of the certificate.

Syntax

dtlsservercontrol.SSLCertThumbprintSHA256

Default Value

""

Remarks

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.

This property is read-only.

Data Type

String

SSLCertUsage Property (DTLSServer Control)

The text description of UsageFlags .

Syntax

dtlsservercontrol.SSLCertUsage

Default Value

""

Remarks

The text description of SSLCertUsageFlags.

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.

This property is read-only.

Data Type

String

SSLCertUsageFlags Property (DTLSServer Control)

The flags that show intended use for the certificate.

Syntax

dtlsservercontrol.SSLCertUsageFlags

Default Value

0

Remarks

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

Please see the SSLCertUsage property for a text representation of SSLCertUsageFlags.

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

This property is read-only.

Data Type

Integer

SSLCertVersion Property (DTLSServer Control)

The certificate's version number.

Syntax

dtlsservercontrol.SSLCertVersion

Default Value

""

Remarks

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

This property is read-only.

Data Type

String

SSLCertSubject Property (DTLSServer Control)

The subject of the certificate used for client authentication.

Syntax

dtlsservercontrol.SSLCertSubject[=string]

Default Value

""

Remarks

The subject of the certificate used for client authentication.

This property must be set after all other certificate properties are set. When this property is set, a search is performed in the current certificate store to locate a certificate with a matching subject.

If a matching certificate is found, the property is set to the full subject of the matching certificate.

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:

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

Data Type

String

SSLCertEncoded Property (DTLSServer Control)

The certificate (PEM/Base64 encoded).

Syntax

dtlsservercontrol.SSLCertEncoded[=string]

Default Value

""

Remarks

The certificate (PEM/Base64 encoded). This property is used to assign a specific certificate. The SSLCertStore and SSLCertSubject properties also may be used to specify a certificate.

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

To read or write binary data to the property, a Variant (Byte Array) version is provided in .SSLCertEncodedB.

This property is not available at design time.

Data Type

Binary String

Config Method (DTLSServer Control)

Sets or retrieves a configuration setting.

Syntax

dtlsservercontrol.Config ConfigurationString

Remarks

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

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the control, 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.

Disconnect Method (DTLSServer Control)

This method disconnects the specified client.

Syntax

dtlsservercontrol.Disconnect ConnectionId

Remarks

Calling this method will disconnect the client specified by the ConnectionId parameter.

DoEvents Method (DTLSServer Control)

This method processes events from the internal message queue.

Syntax

dtlsservercontrol.DoEvents 

Remarks

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

PauseData Method (DTLSServer Control)

This method pauses data reception.

Syntax

dtlsservercontrol.PauseData ConnectionId

Remarks

This method pauses data reception for the connection identified by ConnectionId when called. While data reception is paused, the DataIn event will not fire for the specified connection. Call ProcessData to reenable data reception.

ProcessData Method (DTLSServer Control)

This method reenables data reception after a call to PauseData .

Syntax

dtlsservercontrol.ProcessData ConnectionId

Remarks

This method reenables data reception for the connection identified by ConnectionId after a previous call to PauseData. When PauseData is called, the DataIn event will not fire for the specified connection. To reenable data reception and allow DataIn to fire, call this method.

Note: This method is used only after previously calling PauseData. It does not need to be called to process incoming data by default.

Reset Method (DTLSServer Control)

This method will reset the control.

Syntax

dtlsservercontrol.Reset 

Remarks

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

SendBytes Method (DTLSServer Control)

This method sends binary data to the specified client.

Syntax

dtlsservercontrol.SendBytes ConnectionId, Data

Remarks

This method sends binary data to the client identified by ConnectionId. For example:

byte[] dataToSend = new byte[] { 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33 }; foreach (DTLSConnection c in dtlsserver.Connections.Values) { dtlsserver.SendBytes(c.ConnectionId, dataToSend); }

To send text, use the SendText method instead.

SendText Method (DTLSServer Control)

This method sends text to the specified client.

Syntax

dtlsservercontrol.SendText ConnectionId, Text

Remarks

This method sends text to the client identified by ConnectionId. For example:

string dataToSend = "Hello world!"; foreach (DTLSConnection c in dtlsserver.Connections.Values) { dtlsserver.SendText(c.ConnectionId, dataToSend); }

To send binary data, use the SendBytes method instead.

Shutdown Method (DTLSServer Control)

This method shuts down the server.

Syntax

dtlsservercontrol.Shutdown 

Remarks

This method shuts down the server. Calling this method is equivalent to calling StopListening and then breaking every client connection by calling Disconnect.

StartListening Method (DTLSServer Control)

This method starts listening for incoming connections.

Syntax

dtlsservercontrol.StartListening 

Remarks

This method begins listening for incoming connections on the port specified by LocalPort. Once listening, events will fire as new clients connect and data are transferred.

To stop listening for new connections, call StopListening. To stop listening for new connections and to disconnect all existing clients, call Shutdown.

StopListening Method (DTLSServer Control)

This method stops listening for new connections.

Syntax

dtlsservercontrol.StopListening 

Remarks

This method stops listening for new connections. After being called, any new connection attempts will be rejected. Calling this method does not disconnect existing connections.

To stop listening and to disconnect all existing clients, call Shutdown instead.

Connected Event (DTLSServer Control)

This event is fired immediately after a connection completes (or fails).

Syntax

Sub dtlsservercontrol_Connected(ConnectionId As Integer, SourceAddr As String, SourcePort As Integer, StatusCode As Integer, Description As String)

Remarks

This event is fired immediately after a connection completes (or fails). The ConnectionId parameter indicates the unique ID assigned to this connection.

SourceAddr contains the IP number (Internet address) of the remote party, and SourcePort contains the port from which the packet originated.

If the connection is made normally, StatusCode is 0 and Description is "OK".

If the connection fails, StatusCode has the error code returned by the system. Description contains a description of this code. The value of StatusCode is equal to the value of the system error.

Please refer to the Error Codes section for more information.

ConnectionRequest Event (DTLSServer Control)

This event is fired when a request for connection comes from a remote host.

Syntax

Sub dtlsservercontrol_ConnectionRequest(Address As String, Port As Integer, Accept As Boolean)

Remarks

This event indicates an incoming connection. The connection is accepted by default. Address and Port will contain information about the remote host requesting the inbound connection. If you want to refuse it, you can set the Accept parameter to False.

DataIn Event (DTLSServer Control)

This event is fired when data is received.

Syntax

Sub dtlsservercontrol_DataIn(ConnectionId As Integer, Datagram As String)

Remarks

The DataIn event is fired every time a new datagram is received.

ConnectionId indicates the unique Id of the DTLSConnection from which the packet originated.

Datagram contains the packet as sent by the remote host.

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.

Disconnected Event (DTLSServer Control)

This event is fired when a connection is closed.

Syntax

Sub dtlsservercontrol_Disconnected(ConnectionId As Integer, StatusCode As Integer, Description As String)

Remarks

If the connection is broken normally, StatusCode is 0, and Description is "OK".

If the connection is broken for any other reason, StatusCode has the error code returned by the system. Description contains a description of this code. The value of StatusCode is equal to the value of the system error. The corresponding Visual Basic error code can be obtained by adding 15001 to this value.

Please refer to the Error Codes section for more information.

Error Event (DTLSServer Control)

This event fires information about errors during data delivery.

Syntax

Sub dtlsservercontrol_Error(ConnectionId As Integer, ErrorCode As Integer, Description As String)

Remarks

The Error event is fired in case of exceptional conditions during message processing. Normally, the control fails with an error.

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

ConnectionId indicates the connection for which the error is applicable.

Log Event (DTLSServer Control)

This event fires once for each log message.

Syntax

Sub dtlsservercontrol_Log(ConnectionId As Integer, LogLevel As Integer, Message As String, LogType As String)

Remarks

This event fires once for each log message generated by the control. The verbosity is controlled by the LogLevel setting.

LogLevel indicates the level of message. Possible values are as follows:

The value 1 (Info) logs basic information, including users logging in and out, files transferred, and directories listed.

The value 2 (Verbose) includes logs from the PITrail event as well as basic information about data transfer channels.

The value 3 (Debug) logs additional debug information, such as extended socket connection and data transfer information.

Message is the log entry.

LogType identifies the type of log entry. Possible values are as follows:

• "Info"
• "Error"
• "Verbose"
• "Debug"

SSLClientAuthentication Event (DTLSServer Control)

This event is fired when the client presents its credentials to the server.

Syntax

Sub dtlsservercontrol_SSLClientAuthentication(ConnectionId As Integer, CertEncoded As String, CertSubject As String, CertIssuer As String, Status As String, Accept As Boolean)

Remarks

This event enables the server to decide whether or not to continue. The Accept parameter is a recommendation on whether to continue or to 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").

SSLStatus Event (DTLSServer Control)

This event is fired to show the progress of the secure connection.

Syntax

Sub dtlsservercontrol_SSLStatus(ConnectionId As Integer, Message As String)

Remarks

The event is fired for informational and logging purposes only. It is used to track the progress of the connection.

Config Settings (DTLSServer Control)

DTLSServer Config Settings

UDP Config Settings

Socket Config Settings

SSL Config Settings

-----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-----

-----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-----

-----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-----

Base Config Settings

Trappable Errors (DTLSServer Control)

DTLSServer Errors