Hi, I am using the following iptables rules for the NAT, but i also want to block outgoing port 25 traffic from the LAN clients. INAT works fine but the outgoing port 25 is still open /sbin/iptables -F -t nat /sbin/iptables -A INPUT -p tcp -i eth0 -s 0/0 -d ! 10.0.0.0/8 --dport 25 -j REJECT /sbin/iptables -t nat -A POSTROUTING -o eth1 -j MASQUERADE But the outgoing port 25 is still open, can some tell me whats wrong in these rules. Regards Azher