[11067] in North American Network Operators' Group
Re: default routes on Ciscos
daemon@ATHENA.MIT.EDU (Paul A Vixie)
Sat Jul 19 16:43:22 1997
To: nanog@merit.edu
In-reply-to: Your message of "Fri, 11 Jul 1997 10:30:58 EDT."
<Pine.A41.3.95.970711102825.38240A-100000@tiger.middlebury.edu>
Date: Sat, 19 Jul 1997 13:14:39 -0700
From: Paul A Vixie <vixie@vix.com>
> Just curious if anyone out there knows of a way to configure default
> routes on a per interface basis on a Cisco. So that different interfaces
> had different default routes statically defined.
Others here have pointed out that this can be done using policy based routing.
It's pretty hard to do per-interface default routes when you're not the sink
for the packets, though, since there's otherwise no protocol control block or
other state to hang the outbound default on. I suppose you could just do round
robin for your outbound traffic.
If you're using a BSD/OS, NetBSD, or FreeBSD machine and you're doing multi-
homed web service (which _does_ give you protocol control blocks to use to
hold your default route binding for outbound packets), there's some free code
available to support per-interface default routes. It's a small change to the
kernel and an even smaller one to the "route" and "netstat" commands.
See ftp://ftp.vix.com/pub/vixie/ifdefault/ for source code and SF NANOG slides.
