ICQ
In ICQ under "Preferences & security", "Preferences" and Connections, click on "I am behind a firewall or proxy" then click on "Firewall Settings". Then select "I don't have a SOCKS Proxy server on my firewall" or "I am using another Proxy server". Click Next. Click "Use the following TCP listen ports for incoming event" and set the TCP ports for 20000 to 20019 for the first user, 20020 to 20039 for the second user, 20040 to 20059 for the third user, etc.
OUT UDP 4000
IN TCP 20000 - 20019 for one user
Ich hoffe, das bringt dich ein wenig weiter.