Iptables Block MSN
This is iptables config stored under /etc/sysconfig/iptables :
(eth0 = WAN interface, eth1 = LAN interface)
You’ll notice 192.168.1.16 is allowed to connect to any services
*filter :INPUT DROP [0:0] :FORWARD DROP [0:0] :OUTPUT ACCEPT [0:0]
# Basic protections against syn floods and other stuff-A FORWARD -p tcp --syn -m limit --limit 1/s -j ACCEPT -A FORWARD -p tcp --tcp-flags SYN,ACK,FIN,RST RST -m limit --limit 1/s -j ACCEPT
-A FORWARD -p icmp --icmp-type echo-request -m limit --limit 1/s -j ACCEPT
# Block MSN-I FORWARD -s 192.168.1.0/24 -p tcp -m tcp --dport 1863 -j DROP -I FORWARD -s 192.168.1.0/24 -p tcp -m tcp --dport 1863 -j LOG --log-prefix "MESSENGER MSN > "
-I FORWARD -s 192.168.1.16 -p tcp -m tcp --dport 1863 -j ACCEPT
# Block AIM/ICQ-I FORWARD -s 192.168.1.0/24 -d 64.12.25.0/22 -j DROP -I FORWARD -s 192.168.1.0/24 -d 64.12.25.0/22 -j LOG --log-prefix "MESSENGER ICQ/AIM > "
-I FORWARD -s 192.168.1.16 -d 64.12.25.0/22 -j ACCEPT
# Block Yahoo IM-I FORWARD -s 192.168.1.0/24 -d 216.155.193.0/22 -j DROP -I FORWARD -s 192.168.1.0/24 -d 216.155.193.0/22 -j LOG --log-prefix "MESSENGER YIM > "
-I FORWARD -s 192.168.1.16 -d 216.155.193.0/22 -j ACCEPT
# Allowing anything else-A FORWARD -i eth1 -o eth0 -m state --state NEW,ESTABLISHED,RELATED -j ACCEPT -A FORWARD -i eth0 -o eth1 -m state --state ESTABLISHED,RELATED -j ACCEPT
