> Hi, > > > > I just implement a center firewall (iptables) with transparent proxy > (squid) > in my company. I block the msn and yahoo chatting program in my iptables > rules. However, the users still can use external free proxy to use msn and > yahoo messenger. May I know got any way for me to block the users for > doing > this and force all the traffic must go though my proxy? MSN (and Yahoo ?) also connects via http and (both ?) use multiple IP addresses. That's why Squid will proxy for MSN clients and you be able to block it using Squid. There have been posts on how to do this and you can easily find them using Google : http://www.google.nl/search?hl=nl&q=block+msn+squid&meta= These may be helpful : http://nscsysop.hypermart.net/no_chat.html http://www.experts-exchange.com/Security/Firewalls/Q_20610865.html Gr, Rob
