Re: proxy arp issues

From: Vikram (vvikram@stanford.edu)
Date: Thu Mar 21 2002 - 15:31:49 EST


ah! thanks. i misread your mail/read it too fast. my bad.

you are right, adding a host-specific route does make the packets appear
on the tunnel interface. thanks a lot.

now let me see if i have any other problem to report:):)

regards,
        Vikram

On Thu, 21 Mar 2002, Vikram wrote:

>
> > Linux will not proxy arp for an address on interface X if the route for
> > that address points back to interface X (That's what you call a routing
> > loop). Do have have a host-specific route for the address that points
> > somewhere else? If you want to use iptables REDIRECT target to capture
> > the traffic, then I think a simple "route add -host b.stanford.edu dev
> > lo" will work.
>
>
> one sec...i dont think i gave you the full details.
>
> i understand your point about the routing loop. my method is something
> like this:
>
>
> yes a.stanford.edu does proxy arp for b.stanford.edu though there is no
> route setup etc
>
> however i want to use NAT/iptables and DNAT the packet which comes into
> the interface [because of the proxy arp] and tunnel it via another
> interface to a new destination .
>
> of course the tunnel is setup properly and in general the DNAT works
> but the packet never seems to come because there never seems to be a
> arp-reply from the comp
>
> hope i was clear.
> Vikram
>
>
>
>
> >
> > Vikram wrote:
> >
> > >Hi,
> > >
> > >I am having trouble using proxy arp with RH7.2 [linux 2.4.7-10 stock
> > >kernel which comes with it]
> > >
> > >Proxy arp doesnt seem to work. I have hosts a.stanford.edu and
> > >b.stanford.edu on the same subnet. b.stanford.edu is no longer there, and
> > >a.stanford.edu is set to proxy arp for it....so that it can get its
> > >packets [for a specific reason which is not so relevant here,hopefully].
> > >
> > >i set the proxy arp entry in a.stanford.edu as follows:
> > >
> > >arp -Ds b.stanford.edu eth0 pub
> > >
> > >and then ping b.stanford.edu from some host outside. a tcpdump shows the
> > >gateway router doing an arp who-has b.stanford.edu but there is no arp
> > >reply at all from a.stanford.edu ??
> > >
> > >can anyone tell me what i have missed ?
> > >
> > >
> > > Vikram
> > >
> > >-
> > >To unsubscribe from this list: send the line "unsubscribe linux-net" in
> > >the body of a message to majordomo@vger.kernel.org
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> > >
> >
> >
> > --
> > Casey Carter
> > Casey@Carter.net
> > ccarter@uiuc.edu
> > AIM: cartec69
> >
> >
> >
> > -
> > To unsubscribe from this list: send the line "unsubscribe linux-net" in
> > the body of a message to majordomo@vger.kernel.org
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> >
>
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