From mboxrd@z Thu Jan  1 00:00:00 1970
From: Martin van den Berg <martinvdberg@gmail.com>
Subject: Forwarding packets on same interface (echoing)
Date: Fri, 12 Aug 2005 13:05:26 +0200
Message-ID: <5edf245205081204055a3363f2@mail.gmail.com>
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G'day,

I have this NAT/firewall box (debian) configured with iptables. Port
forwarding etc works fine for one exception: A need a rule that
'echoes' back udp packets if they meet the following criteria:
+ in-interface=3Deth1 (that's the 'private' interface)
+ destination IP is public ip-address (e.g. 1.2.3.4) (that's eth0)
+ Port range is e.g. 30000-32000
+ The packets need to be forwarded via eth0 (thus echoed) to e.g.
10.10.1.2, same port.

Hope you can help me and thanks in advance!

Martin.