The IP address is most likely included to prevent abuse, by logging a fairly reliable indication of the source of the connection (or at least a cooperating middle agent). The most common reason to want something else there is if someone is going to engage in a fraudulant action (like sending spam using a third-party relay).

Are you saying you want to be abused, or that you want to abuse someone else? It's still not clear from the message. If you merely don't want to show it, then simply remove it from the CGI script. If you want to alter it, then come at the machine from a different address. There's really no ordinary way to just "set" it.

-- Randal L. Schwartz, Perl hacker