Re: [SLUG] IPtables DNAT question

[Phil Scarratt <fil@xxxxxxxxxxx>]

Peter Rundle wrote:
> Sluggers,
>
> I'm D'nating access to my web server via my Linux Gateway with this 
> statement.
>
>    iptables -t nat -A PREROUTING -p tcp -i eth0 --dport 80 -j DNAT --to 
> 172.16.0.148
>
> This works great as long as the default gateway on the web server 
> (172.16.0.148) points to the Linux Gateway.
>
> However, I need to set the default gateway of the web server to 
> somewhere else (an alternate internet connection) When I do this the 
> reply packets never make it back to the gateway, and I have an asymetric 
> routing situation (Kinda as expected really).
>
> My Question is;
>
> Is there a complimentary iptables statement that I can use to SNAT's the 
> inbound packet so that the web server
> see's the source as the Linux gateway hence the packet is returned there 
> where upon it is readdressed back to the real originating client in the 
> outside world?
>
> I know that I can put Apache on the Linux Gateway and reverse-proxy 
> but... just wondering if there was
> "a better way (tm)"
>
> TIA's
>
> P.

I've never had to use SNAT but it does exist, so presumably it can do 
what you want it to. Checkout the man page for iptables or I'm sure 
there's a howto somewhere.

Fil