Gateway?

I'm looking for either a plug in for my e-smith server/gateway or a new server/gateway where I can restrict workstations from internet access based on either ip address or login. Anyone know of such a system? I need to be able to do content filtering too. Right now I have squidguard installed for that purpose.

Tom Achtenberg
SQL Programmer, Information Technologies
Food for the Hungry / US
(480) 609-7750 (voice)
(480) 443-1420 (fax)
TomA@fh.org