From mboxrd@z Thu Jan  1 00:00:00 1970
From: Mohammad Khan <mkhan@lextranet.com>
Subject: Let me understand *RETURN*
Date: Fri, 18 Feb 2005 11:15:58 -0500
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To: 'netfilter' <netfilter@lists.netfilter.org>

I have couple of chains and rules for filter table

-N TCP_IN
-N TCP_OUT
-N UDP_IN
-N UDP_OUT
-N ICMP_IN
-N ICMP_OUT

-N P1_IN
-N P1_OUT
-N P2_IN
-N P2_OUT

-A FORWARD -d IP_OF_P1 -j P1_IN
-A FORWARD -s IP_OF_P1 -j P1_OUT

-A FORWARD -d IP_OF_P1 -j P1_IN
-A FORWARD -s IP_OF_P1 -j P1_OUT
-A FORWARD -j LOG --log-prefix "NOT_FORWARDED "
-A FORWARD -j DROP

-A P1_IN -t TCP -j TCP_IN
-A P1_IN -t UDP -j UDP_IN
-A P1_IN -t ICMP -j ICMP_IN
-A P1_IN -j RETURN

-A TCP_IN -t TCP --dport 80 -J ACCPET
-A TCP_IN -j RETURN

For any tcp packet that going to P1 and don't have destination port 80: 

returned to P1_IN chain from TCP_IN chain, then after
returned to FORWARD chain from P1_IN, and finally
dropping the packet after kept log.

Am I right?

MOhammad