If you are using the Telnet proxy type, the usual command required by the firewall's Telnet server is connect, followed by a host name and a port number. If your proxy needs a different command, you can enter an alternative in the ‘Command to send to proxy’ box.
If you are using the Local proxy type, the local command to run is specified here.
If you are using the ‘SSH to proxy and execute a command’ type, the command to run on the SSH proxy server is specified here. Similarly, if you are using ‘SSH to proxy and invoke a subsystem’, the subsystem name is constructed as specified here.
In this string, you can use \n to represent a new-line, \r to represent a carriage return, \t to represent a tab character, and \x followed by two hex digits to represent any other character. \\ is used to encode the \ character itself.
Also, the special strings %host and %port will be replaced by the host name and port number you want to connect to. For Telnet and Local proxy types, the strings %user and %pass will be replaced by the proxy username and password (which, if not specified in the configuration, will be prompted for) – this does not happen with SSH proxy types (because the proxy username/password are used for SSH authentication). The strings %proxyhost and %proxyport will be replaced by the host details specified on the Proxy panel, if any (this is most likely to be useful for proxy types using a local or remote command). To get a literal % sign, enter %%.
If a Telnet proxy server prompts for a username and password before commands can be sent, you can use a command such as:
%user\n%pass\nconnect %host %port\n
This will send your username and password as the first two lines to the proxy, followed by a command to connect to the desired host and port. Note that if you do not include the %user or %pass tokens in the Telnet command, then anything specified in ‘Username’ and ‘Password’ configuration fields will be ignored.