Upgrade from IP chains to IP tables

[mjsunil]

Hi, I want to upgrade from ipchains to iptables is there any tool or an easy way to move all the rules from ipchains to iptables

[Alexander Chuzhoy]

what version of linux do you use?
generally
rpm -Uvh iptables-version to install the package of iptables
then
chkconfig ipchains off
chkconfig --del ipchains
to stop using ipchains
chkconfig --add iptables
chkconfig iptables on
to start using iptables

[Stuart Browne]

The hardest part about converting from IPCHains to IPTables is the translating of the rules.

For the most part, the commands are silmiar.

DIfferences lie in the names of the chains (INPUT instead of input, etc.), the way masquerading/NAT work, the fact that there are different tables to put rules in, and that the flow of traffic is slightly different.

Some fundamentels to get you going:

http://www.netfilter.org/documentation/

The HOWTO's here are brilliant.

Basic things to know...

The 'forward' (FORWARD in iptables) chain doesn't see everything. Just stuff of which gets passed from one interface to the other.

Under IPChains, the Forward chain saw everything, including things that were destined for the firewall box. This is not the case in IPTables.

DENY isn't about any more. You want DROP.

'-m ' are your friends! The 'state' module is nearly indespensable!

If you have sepecific issues with rules, post 'em here, we'll give you a hand.