I'm looking for firewall/proxy/gateway/URL filter for my company that can allow/deny user to access internet with these scenarios:
1. A group of user can access to pop3 and smtp only.
2. Deny all access to porn/advertise sites.
3. Allow a group of user to access to certain sites, but deny it to other groups.
I have tried Kerio Winroute Firewall on Windows and it has all those function and I want same features that run on Linux.