Thanks to someone at the Mandriva forum, I found the problem. It was the SQUID proxy cache. And also the ICS wizard wasn't working properly. I tried not enabling SQUID once before to see if that was the problem but I didn't realize that setting wasn't being applied. So I uninstalled and reinstalled Shorewall and did the wizard again and everything is fine now. When I uninstalled Shorewall, I chose complete removal but it didn't do that. I had to delete the Shorewall folder myself.