Hey, I'm very new at iptables and I'm trying to open ports 161 and 162 udp to ip 172.17.1.2.So i need need ports 161 and 162 open for only ip 172.17.1.2.I know the config file I just ned the paramaters.

Thank you

iptables -I INPUT -m udp -p udp --dport 161 -s ! 172.17.1.2/32 -j DROP
iptables -I INPUT -m udp -p udp --dport 162 -s ! 172.17.1.2/32 -j DROP

then save them somewhere, for instance /etc/rc.d/rc.firewall or /etc/rc.d/rc.local, so that they are not lost on a reboot

These rules are for systems that have a default ACCEPT policy. If on the other-hand you have a default DROP policy on your system try the following rules instead:

iptables -I INPUT -m udp -p udp --dport 161 -s 172.17.1.2/32 -j ACCEPT
iptables -I INPUT -m udp -p udp --dport 162 -s 172.17.1.2/32 -j ACCEPT

Thank you, now what if I just wanted to set a rule so only 172.17.1.2 can talk to this machine and this machine can talk to 172.17.1.2 ( open all ports,like dmz)Problem i'm having is trying to open certain ports,but for some reason i'm missing a few ports that need to be open so for testing i would like to grant access so that the linux machine can talk to 172.17.1.2 on all ports and visa virsa.

thanks again