Software question ...

From: Jacek Jurkowski (jjurkowski_at_datacomp.szczecin.pl)
Date: 01/26/05 

Date: Wed, 26 Jan 2005 09:23:45 +0100

Win 2003 server working as a router between
Internet and my local network. I need some tool
to monitor network trafic. My needs are to know:

1) What links and sites are browsed currently by
    users from my internal network.
2) Who browses what.
3) Ports on what connections are establisched.
4) Prefered freeware (i don't need an advanced options
    , just simple informations so it musn't be a big,expensive software).