On Sun, 24 Feb 2002, byte wrote:

> But I want to know why it need BOTH SNAT and DNAT for such mapping..

...to force packet get back through NAT_box [to remap again from 1.4 to
1.1].  If SNAT isn't done then 1.4 reply direct to clent which will be
surprised becouse he did connection to 1.1 ;)
When DNAT isn't done through 1 interface but passes NAT_box [to another
interface that is more popular ;)] than You don't need to do SNAT, all job
is done by conntrack/nat then reply returns. [I suppose again ;)]

This issue is covered in some documentation on netfilter website AFAIR.

> >> -A PREROUTING -p tcp --dport 80 -d 192.168.1.1 -j DNAT --to
> >> 192.168.1.4
> >
> >....and also add SNAT to 192.168.1.1 rule in postrouting.

tw
-- 

----------------
 ck.eter.tym.pl


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