FTP Configuration

When using an active mode configuration (Passive = False) with a firewall, it may sometimes be necessary to specify the actual PORT value to be sent to the server. ActiveModePORTAddress takes the protocol-level parameter in the form "a,b,c,d,e,f" where "a,b,c,d" is the external IP address separated by commas, and e and f represent, respectively, the high byte (divide by 256) and the low byte (mod 256) values of the external port where the FTP client is listening.

This config must be used in conjunction with PortRange to ensure that the correct port is used by the client.

The ActiveModeIP config can be used to specify the IP address that the server will connect to when using an active mode configuarion (Passive = False). When this config is set, the port number where the component listens for active mode connections will still be managed by the component. The PortRange can also be used to ensure that the correct port is used by the client.

Note that this config will be ignored if ActiveModePORTAddress is also specified.

If set to true, the downloaded files will be appended to the file specified in LocalFile.

When set to True, the class sends an FTP "SIZE" command to retrieve the file size before beginning a download. When downloading a large quantity of small files, performance may be increased by disabling this feature.

Some servers will include "total" information when returning a directory listing that contains some non-entry data. When CheckTotalEntry is set to True (default), the component will ignore lines beginning with "total" to account for this. In some cases, it may be desirable to include these lines in the resulting DirList data; this can be done by setting this configuration setting to False.

This property controls how the DI connection is closed. The default is True.

In the case that DILinger is True (default), there are two scenarios for determining how long the connection will linger. The first, if DILingerTime is 0 (default), the system will attempt to send pending data for a connection until the default IP protocol timeout expires.

In the second scenario, DILingerTime is a positive value, the system will attempt to send pending data until the specified DILingerTime 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 class returns control immediately, the system could hold system resources until all pending data is 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 (by a client acknowledgment, for example), setting this property to False might be the appropriate course of action.

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

Sometimes the FTP server will return data in a directory listing that is not entry data and can be ignored. The IgnoreEntries configuration setting takes a comma-separated list of entries to ignore. Only the beginning of the entries need to be specified and correct case is not required.

The default value is "M/d/yyyy hh:mm:ss tt". When set, the class will format the time returned by the server in the FileTime property. To disable all formatting set this to empty string.

Note: This setting only applies to the FileTime property. It does not apply to the FileTime parameter of the DirList event.

When set to use active mode (Passive = False), the class uses any available port to listen to incoming connections from the server. You can override this behavior by setting PortRange to a value containing the range of ports the class will be listening to.

The range is provided as start-end, for instance: "1024-" stands for anything higher than 1024, "1024-2048" stands for ports between 1024 and 2048 inclusive, "4000-4010, 50000-50010" stands for ports between 4000 and 4010 or between 50000 and 50010.

When this value is set to "True" the class will upload the data in the file specified by LocalFile and continue monitoring LocalFile for additional data to upload until no new data is found for RealTimeUploadAgeLimit seconds. This allows you to start uploading a file immediately after the file is created and continue uploading as data is written to the file. The default value is "False".

This value is only applicable when RealTimeUpload is set to "True". This specifies the number of seconds for which the class will monitor LocalFile for new data to upload. If this limit is reached and no new data is found in LocalFile the upload will complete. The default value is "1".

When set, extended passive mode will be used.

When this is set to True the class will list files in the directory using the MLSD command. This command is an extension to the protocol which defines a more standardized and reliable directory listing format. Not all servers support this command. The default value is False.

When set to True, set RemoteFile to the filemask and call either ListDirectory or ListDirectoryLong. There is no difference between the two methods when this setting is enabled.

This setting is similar to UseMLSD except that it is only valid for a single file. When this is set to True the class will list the file or folder specified by RemoteFile. If RemoteFile is not set, a listing for the current directory itself will be returned. This command is an extension to the protocol which defines a more standardized and reliable directory listing format, but for a single file or folder only. Not all servers support this command. The default value is False.

When set to True, set RemoteFile to the file or folder you wish to get information about and call either ListDirectory or ListDirectoryLong. There is no difference between the two methods when this setting is enabled. When both UseMLSD and UseMLST are set, UseMLSD takes precedence.

The default value is false. When set to true the class will issue the "MODE Z" command to the FTP server. This will enable deflate compression so all data transferred is first compressed either by the server (when downloading) or by the class (when uploading). Note that not all servers support this feature.

The default value is 7. Valid values are from 0 to 9. A higher value indicates a higher compression level is used. This is only valid when UseModeZ is set to True.

When this setting is True (default), the class will use the address specified by RemoteHost when establishing a data connection for directory listings and file transfers. When this setting is False, the class will use the address provided by the server in response to the PASV command.

This setting is only applicable when Passive is True.

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

This is the same as FirewallAutoDetect. This setting is provided for use by classs that do not directly expose Firewall properties.

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 is the same as FirewallHost. This setting is provided for use by classs that do not directly expose Firewall properties.

If FirewallHost is specified, the FirewallUser and FirewallPassword settings are used to connect and authenticate to the given firewall. If the authentication fails, the class fails with an error.

NOTE: This is the same as FirewallPassword. This setting is provided for use by classs that do not directly expose Firewall properties.

Note that the FirewallPort is set automatically when FirewallType is set to a valid value.

NOTE: This is the same as FirewallPort. This setting is provided for use by classs that do not directly expose Firewall properties.

The appropriate values are as follows:

NOTE: This is the same as FirewallType. This setting is provided for use by classs that do not directly expose Firewall properties.

If the FirewallHost is specified, the FirewallUser and FirewallPassword settings are used to connect and authenticate to the Firewall. If the authentication fails, the class fails with an error.

NOTE: This is the same as FirewallUser. This setting is provided for use by classs that do not directly expose Firewall properties.

When set, TCPKeepAlive will automatically be set to true. By default the operating system will determine the time a connection is idle before a 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.

Note: This value is not applicable in Java.

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 acknowledgement is received from the remote host the keep-alive packet will be re-sent. This 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 Java or MAC.

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 acknowledgement is received from the remote host the keep-alive packet will be re-sent. This setting specifies the number of times that the keep-alive packets will be re-sent before the remote host is considered disconnected. The system default if this value is not specified here is 9.

Note: This configuration setting is only available in the Unix platform, and isn't supported in Mac OS or FreeBSD.

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

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

In the second scenario, 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 class returns control immediately, the system could hold system resources until all pending data is 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 (by a client acknowledgment, for example), setting this property to False might be the appropriate course of action.

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

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 multi-homed hosts (machines with more than one IP interface) setting LocalHost to the value of an interface will make the class initiate connections (or accept in the case of server classs) only through that interface.

If the class 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 multi-homed hosts (machines with more than one IP interface).

This must be set before a connection is attempted. It instructs the class 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; setting is useful when trying to connect to services that require a trusted port in the client side. An example is the remote shell (rsh) service in UNIX systems.

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. The maximum value is 65536 bytes.

This 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.

If set to a positive value, this setting defines the length of data records to be received. The class will accumulate data until RecordLength is reached and only then fire the DataIn event with data of length RecordLength. This allows data to be received as records of known length. This value can be changed at any time, including within the DataIn event.

The default value is 0, meaning this setting is not used.

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.

When set to 0 (default), the class will use IPv4 exclusively. When set to 1, the class will use IPv6 exclusively. To instruct the class 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:

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

By default, this config is set to false.

If AbsoluteTimeout is set to True, any method which 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 UDP ports.

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).

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 receiving. Increasing the value of the InBufferSize setting can provide significant improvements in performance in some cases.

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

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. Increasing the value of the OutBufferSize setting can provide significant improvements in performance in some cases.

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

If there are no events to process when DoEvents is called, the class will wait for the amount of time specified here before returning. The default value is 20.

The default code page is the Active Code Page (0).

The following is a list of valid code page identifiers:

The following is a list of valid code page identifiers for Mac OS only: