Hi all, I'm using masqueride for my client's internet connection. Here I defined only on port 21, 22, 80, 53, 25, 110, and 443. By this chains rule, all my client can get the access of the internet for ftp, ssh, Web handling, mail (pop3 and smtp) and https. That something I hate, I could not disable the access for Yahoo Messanger : (. YM has its personal proxy managing that can use defined common port as 80 (http port). How can I disable the connection for Yahoo Messanger using IPchains ? It's a good thing too if I can do the same thing for MSN Messanger, and ICQ. Note : - ICQ and MSN could use defined port opened. - This is my simple Chains. ipchains -F ipchains -A forward -s 192.168.21.0/24 -d 0/0 80 -j MASQ -p tcp ipchains -A forward -s 192.168.21.0/24 -d 0/0 80 -j MASQ -p udp ipchains -A forward -s 192.168.21.0/24 -d 0/0 53 -j MASQ -p tcp ipchains -A forward -s 192.168.21.0/24 -d 0/0 53 -j MASQ -p udp ipchains -A forward -s 192.168.21.0/24 -d 0/0 25 -j MASQ -p tcp ipchains -A forward -s 192.168.21.0/24 -d 0/0 25 -j MASQ -p udp ipchains -A forward -s 192.168.21.0/24 -d 0/0 110 -j MASQ -p tcp ipchains -A forward -s 192.168.21.0/24 -d 0/0 110 -j MASQ -p udp ipchains -A forward -s 192.168.21.0/24 -d 0/0 443 -j MASQ -p tcp ipchains -A forward -s 192.168.21.0/24 -d 0/0 443 -j MASQ -p udp ipchains -A forward -s 192.168.21.0/24 -d 0/0 21 -j MASQ -p tcp ipchains -A forward -s 192.168.21.0/24 -d 0/0 21 -j MASQ -p udp ipchains -A forward -s 192.168.21.0/24 -d 0/0 22 -j MASQ -p tcp ipchains -A forward -s 192.168.21.0/24 -d 0/0 22 -j MASQ -p udp