WRT firewalls, every "service" running on the computer runs on a "port." HTTP, mail, telnet, ftp, etc. servers each have incoming port numbers that they "listen" to for requests. The ports used are the same on practically every system out there. Many firewalls are set up "out-of-box" to support only the ports for "standard" services (mostly the ones mentioned above). IRC is another such service, and it requires two ports: one outgoing (for you to make requests of the server) and one incoming (for the IRC server to talk to you). The server generally (and in this case) "listens" on port 113, while the server expects you generally to be "listening" on 6667. Your firewall hardware/software will need to allow outgoing transmissions on port 113, and incoming on 6667 for IRC to work. Some firewalls are set up by default to be "inclusive" (the list of ports shows the only ports that will work), others "exclusive" (the list of ports shows the ports that are not allowed to work), which is why different firewalls/settings would show different results. Whatever the case, you need to set up your firewall to allow communication over these ports before it will work...am I wrong, fellow nerds?