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Re: IP stack question (how to force pkts to not route locally, but go out i: msg#00142

Subject: Re: IP stack question (how to force pkts to not route locally, but go out interfaces regardless of destination)
Hello,

How about changing the preference of the 'local' table (kernel change required)
and inserting a new table (via iptables) that had rules like 
"if src is local, and dest = 192.168.1.1 then send out eth0"

Jim

On Tue, Aug 27, 2002 at 11:25:58PM -0700, Ben Greear wrote:
> 
> jamal wrote:
> > Ben Wrote:
> >>I would actually like to be able to force a machine to not do local
> >>routing as well, and force packets out over an interface even if
> >>the destination is a local IP,  using source-based-routing,
> >>or something similar.  There is no way to do this currently?
> >>
> > 
> > 
> > Try that SO_DONTROUTE and see if solves your problem; you probably have to
> > bind the socket to a specific device as well;
> > For all that trouble, i would suggest you may just as well write a sock
> > packet based  app.
> 
> I am back to trying to figure out how to make this work.  I'm tried source
> based routing, and it does not work (it routes internally).
> 
> I read the help on SO_DONTROUTE, but it seems to make the kernel not able
> to send to a router.  I would like to be able to route, ie port a -> router 
> -> port b
> 
> I already bind to a particular port and IP, and use policy based routing
> (source based routing) to make sure the packet is sent out the correct
> local interface.
> 
> I just need to find the routing logic that notices the destination IP is local
> and tell it to quit looking (probably for a particular socket, as I can
> see how this could break applications who didn't expect it)
> 
> I dug through the code once before looking for this, and didn't find
> what I needed.  Can anyone suggest the right files and/or methods to
> look in?
> 
> Thanks,
> Ben
> 
> > 
> > cheers,
> > jamal
> > 
> 
> 
> -- 
> Ben Greear <greearb@xxxxxxxxxxxxxxx>       <Ben_Greear AT excite.com>
> President of Candela Technologies Inc      http://www.candelatech.com
> ScryMUD:  http://scry.wanfear.com     http://scry.wanfear.com/~greear
> 
> 

-- 
James R. Leu




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