Looking for a network sniffer that collects a used-ports list to help preparing a portfilter firewall script

[Christian Hammers <ch@lathspell.de>]

Hello

I remember a network sniffer that could be run e.g. over a week to collects a
list of all used tcp/udp ports which could then be used as base for creating a
firewall script for hosts.

Does anybody know the name of this tool?

bye,

-christian-