There are several commands that are not used in determining if a request is destined for a remote site, but are used to configure other aspects of the SOCKS shim: BIND-MODULE        Tells the SOCKS shim that the named application uses incoming connections from beyond the SOCKS server. Multiple BIND-MODULE statements can appear in the socks.cnf file, one of each application that needs this feature. The only Windows application that uses this feature is the FTP program. EXCLUDE-MODULE        Tells the SOCKS shim that the named application should assume DIRECT 0.0.0.0.0.0.0.0 for every connection. This command is not normally needed, but may be used for circumstances where, for security reasons, the system administrator does not want users to run a particular application to connect to hosts outside the SOCKS server. PROXY-NAME        Used to facilitate the DNS lookup of names. If an attempt is made to connect to a host and the name of the host fails local translation, then the SOCKS V5 connection attempt is made via the name, through the specified serverlist. Since the IP address is not known, this command has its own list of SOCKS V5 servers. BALANCE        Randomly rearranges the order of SOCKS servers listed in a serverlist on SOCKDx lines, which are listed after this command in the socks.cnf file. The order is constant for all connections within the application, but changes each time the application is run. This allows for load balancing where a site has several SOCKS servers. GSS        Sets the encryption method.

Adjusting the Port Number

By default, a SOCKS server is assumed to be on port 1080. You can specify a specific port number by following a server address or name with a colon (:) and port number. The following example shows how you would use port 1081.

192.168.100.205:1081

mysockserver:1081

Processing Requests

On an attempted connection, each line is processed in order and the first line that matches the entered address is used. If no line matches the address, DIRECT is assumed. To cause all non-specified addresses to fail, place the following line at the end of the file: DENY 0.0.0.0 0.0.0.0

A line is matched by passing the following tests:

1. The destination address is indicated with dst_mask. The resultant address must be equal to dst_addr.
2. If you specified a userlist, the current username must match an entry in the list. Note that comparisons are not case sensitive.
3. If you specified op dst_port, the destination port must satisfy the specified operator and dst_port.

If a line is matched, the following occurs:

• DENY - The connection is disallowed. A Connection Refused error message is returned.
• DIRECT - The connection is processed as if the SOCKS support was not present.
• SOCKD, SOCKD4 - The connection is attempted through a SOCKS V4 server.
• SOCKD5 - The connection is attempted through a SOCKS V5 server.

If @=serverlist is present, the connection is attempted by connecting to successive servers in the list. If @=serverlist is not present, a server name or IP address is taken from the following registry entry:

HKEY_LOCAL_MACHINE\SOFTWARE\Hummingbird\Connectivity\7.00\Socks

As is the case with serverlist entries, the registry entry may specify an explicit port number followed by the server address or server name with a colon (:) port number sequence.

You can edit the configuration file at any time. After you make the changes, all applications you open use the new settings.

SOCKS Example

In the following example the system administrator is on the network at 192.168.100.x and the socks server is at 192.168.100.205. All TCP/UDP traffic to systems on the 192.168.100 net are connected directly, while traffic to all other addresses goes through the SOCKS server.

DIRECT 192.168.100.0 255.255.255.0

SOCKD5 @=192.168.100.205 0.0.0.0 0.0.0.0