Problem with SNAT

Jason Opperisano opie at 817west.com
Thu Sep 2 22:17:51 CEST 2004


On Thu, 2004-09-02 at 14:57, Bgs wrote:
>   Greetings,
> 
> I have problems with the following setup:
> 
> A linux with two NICs. One with IP of 10.0.2.2 and one with 10.0.3.57.
> I have DNAT-ed traffic coming in on the 10.0.2.2 that was originally 
> sent to 10.0.2.1. (Another node doing the DNAT). I have problems on the 
> route back so I decided to SNAT the backward udp traffic to  soource 
> 10.0.2.1 and send the SNATed packets back on another route.
> 
> I added the line to nat postrouting (-d target_net -s 10.0.2.2 -p udp -j 
> SNAT --to-source 10.0.2.1) but the packages don't even seem to hit the 
> nat postrouting chain. Let alone my SNAT rule.
> 
> Any ideas what could be wrong ?
> 
> Thanks
> Bgs

since i have to guess (hint:  post your rules [1] if you want us to find
the problem for you)...

i would say that your filter rules drop the packet before they ever get
to the POSTROUTING chain of the nat table.

-j

[1] - iptables -vnL && iptables -t nat -vnL && iptables -t mangle -vnL

-- 
Jason Opperisano <opie at 817west.com>




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