How to block outgoing traffic to specific websites

[Sheila R. White]

Help   Redhat 7.2 Box is being used as an email server/and a way for internal users to access the internet. Livingston router/firewall is also being used.   My question is...How do I prevent users from accessing certain sites, for instance---http://games.yahoo.com/.   Can i do this with iptables and how??? do i vi iptables edit and save?? IPTABLES Chain INPUT (policy ACCEPT) target prot opt source destination Chain FORWARD (policy ACCEPT) target prot opt source destination ACCEPT all -- xxx.0.0.0/8 anywhere ACCEPT all -- xxx.0.0.0/8 anywhere Chain OUTPUT (policy ACCEPT) target prot opt source destination Can I accomplish this also with the hosts file like windows os.? Thank You All in Advance