RedHat 9 by today's standards is quite dated. Fedora Core 3 is the current offerings by redhat (which is sorta based on community involvement) and FC4 release is impending.
The other stuff I'm not sure what you are refering to. A more detailed description of the problem, protocol, software in use and the desired end result would be helpful. It does sound like an ipfilter issue, but with technology I try not to make a guess.