From: John Madden <jmadden@ivytech.edu>
To: Grant Taylor <gtaylor@riverviewtech.net>
Cc: Mail List - Netfilter <netfilter@vger.kernel.org>
Subject: Re: "DNAT" w/o changing source address?
Date: Thu, 04 Oct 2007 09:14:02 -0400 [thread overview]
Message-ID: <1191503642.13379.12.camel@localhost.localdomain> (raw)
In-Reply-To: <47042728.1060508@riverviewtech.net>
> Um, correct me if I'm wrong, but Destination NATing should not alter the
> source IP address of the packet that is being NATed.
>
> Honestly, I wonder how you are doing your DNATing and if you are not
> also possibly unknowingly SNATing as well.
Hmm, well here are the rules I'm running. The port forward:
echo "1" > /proc/sys/net/ipv4/ip_forward
iptables -t nat -A PREROUTING -d $EXTIP -p tcp --dport 25 -j DNAT --to
$MAILSERVER:25
And the SNAT for return traffic:
iptables -t nat -A POSTROUTING -d $MAILSERVER -j SNAT --to $EXTIP
...At least, I found that traffic wouldn't flow without this additional
rule. Have I gotten something else fundamentally wrong here?
John
--
John Madden
Sr. UNIX Systems Engineer
Ivy Tech Community College of Indiana
jmadden@ivytech.edu
next prev parent reply other threads:[~2007-10-04 13:14 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-03 15:21 "DNAT" w/o changing source address? John Madden
2007-10-03 23:35 ` Grant Taylor
2007-10-03 23:50 ` Pascal Hambourg
2007-10-04 1:17 ` Grant Taylor
2007-10-04 13:14 ` John Madden
2007-10-04 13:14 ` John Madden [this message]
2007-10-04 14:09 ` Grant Taylor
2007-10-04 14:19 ` John Madden
2007-10-04 15:13 ` Grant Taylor
2007-10-04 14:17 ` Pascal Hambourg
2007-10-04 14:22 ` John Madden
2007-10-04 14:59 ` Pascal Hambourg
2007-10-04 15:13 ` John Madden
2007-10-04 15:29 ` Grant Taylor
2007-10-04 19:33 ` Grant Taylor
2007-10-04 16:01 ` Pascal Hambourg
2007-10-04 15:23 ` Grant Taylor
2007-10-04 15:52 ` Pascal Hambourg
2007-10-04 19:12 ` Grant Taylor
2007-10-04 19:25 ` John Madden
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