Sobari Tanuwijaya wrote: > Where should I put this? After the command Barry said for before? it doesn't matter, its a rule in a different chain I recommend you read up on iptables and firewall rules to understand how it all works before attempting to apply any rule. good stuff here http://www.netfilter.org/documentation/ the ip masquerade HOWTO lives here http://tldp.org/HOWTO/html_single/IP-Masquerade-HOWTO/ its a -little- out of date, but still quite applicable. these additional rules should be added in a manner compatible with your existing firewall rules... if you're using one of the common rule generator scripts (lokkit, shorewall, etc) it may well already have its own method for enabling rules like this, that would be preferable.