Hello to all! I have to block access to certain sites to a network of PCs.
On the server - firewall I wrote:
iptables -A OUTPUT -d ip_site_to_be_blocked -j DROP
If I try to ping me error (and before restarting the service: /etc/init.d/iptables restart, this error was not there)
But the client (windows 7) continues to make the table correctly (after the restart) .. how to solve?

ps: this is squid as a proxy server, but in the configuration file is written that has been disabled (but do not know how and I can not start it again)