Re: [Nolug] http (or any) request via secondary nic

From: Petri Laihonen <pietu_at_weblizards.net>
Date: Tue, 25 May 2010 21:38:26 -0500
Message-ID: <AANLkTinEvdahMgaCPp3sp1OLY-D1Ta5Dp_oPA_POg0-K@mail.gmail.com>

Actually I'm looking a way to direct a traffic (requests and responses) via
different NIC.

For instance, if I run "ping", by default it wants to use the primary NIC
(eth0). Therefore by pinging the IP address over the crossover cable
(private net) there are no results because it was not found. If I specify
the interface eth1 for the ping, then the IP address responds.

for example:
ping 192.168.2.251 (results nothing)
ping -I eth1 192.168.2.251 (responses are as expected)

But instead of ping, I would like to be able to do this with pretty much any
process I see fit.

This is easy with the applications which support defining the network
interface such as ping and curl, but any other programs, what methods would
there be available. I suspect iptables could be the one, but exactly
how.....

P

On Tue, May 25, 2010 at 9:23 PM, Charles Paul <charles.paul@gmail.com>wrote:

> If Petri is looking to route packets based on the destination port,
> say port 80 traffic through gw2 and the rest through gw1, he should
> follow the instructions on this FAQ:
>
> http://www.linuxhorizon.ro/iproute2.html
>
>
>
> On 5/25/10, Jerry Wilborn <jerrywilborn@gmail.com> wrote:
> > iptables -t nat -A POSTROUTING -o eth0 -d 1.1.1.1 -j SNAT --to-source
> > 2.2.2.2
> >
> >
> > This will source traffic destined for 1.1.1.1 with a source of 2.2.2.2.
> > Paint to match, etc.
> >
> > If you're using a program like 'curl' then you can use a switch like
> > '--interface'.
> >
> > Jerry Wilborn
> > jerrywilborn@gmail.com
> >
> >
> > On Tue, May 25, 2010 at 6:25 PM, Petri Laihonen <pietu@weblizards.net
> >wrote:
> >
> >> Hey,
> >>
> >> Is it possible to direct a process on the server to use eth1 instead of
> >> eth0 for outgoing request?
> >>
> >> For instance, one can request PING command to use specified interface.
> How
> >> about links (or Lynx), or cli script etc...
> >>
> >> If this does not work in the application level, how about some sort of
> >> rule
> >> in the firewall, which would direct a request for
> >> http://exampledomain.tldvia eth1 instead of default eth0?
> >>
> >> Petri
> >>
> >
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>

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Received on 05/25/10

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