try this
http://www.amule.org/wiki/index.php/Firewall
kazaa actually defaults to port 80 if it cant have access to the standard ports. The main kazaa port is 1245, but you should be able to force it to use any port you want. you should really try limewire though, as it is easier to do this and actually made for linux- and is much much cleaner than kazaa and much much faster at searches..