UPDATE: Version 1.2.6 and later support the entry of alternate FTP ports on the Protocols tab of the Surrogate Socket Service Control program.

In order to redirect FTP data requests, Surrogate Socket must inspect the data flowing across the FTP command connection on port 21 looking for the PORT command from the FTP client. By default, Surrogate Socket only inspects data flowing across port 21. A new feature added in version 1.1.19 allows you to specify additional ports for Surrogate Socket to inspect for FTP PORT commands.

To enable other ports to be used for FTP command ports, you must add some additional keys to the NT Registry. To do this:

• Run REGEDT32.EXE and select the HKEY_LOCAL_MACHINE window.
• Locate the key HKEY_LOCAL_MACHINE\System\CurrentControlSet\ Services\SurrogateSocket\Parameters and double-click on it in the left pane.
• Select Add Value from the Edit menu.
• Enter AltFTPPort1 for the value name and REG_SZ for the data type.
• Click OK.
• For the String Value, enter the port number you wish to use for FTP command connections. To add additional ports, add additional values with names: AltFTPPort2, AltFTPPort3, etc.

For example, to add port 2000 as an alternate FTP command port, you would add the value AltFTPPort1 and set its value to 2000 as shown below:

After making the above change, you must cycle the Surrogate Socket service.