IPTables how to read the rules?

thllgo · 02-16-2009, 04:49 PM

Hello

I have a question about how to read the /etc/sysconfig/iptables file under RedHat. I thought it was from top down and IPTables would accept the first rule in found that matched.

If this is so why is the rule

:INPUT DROP [0:0]

at the top? I'm guessing this rule is special or IPTables reads all the rules and somehow makes a decision?

Thank you

gilead · 02-16-2009, 05:26 PM

That looks like the policy for the INPUT chain. iptables traverses the list of rules and follows a matching rule (or rules if the previous match returned to the chain). The policy is applied if all of the rules are checked and none match.

The netfilter docs explain this much better than I do...