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I have multiple routers.

(WAN) Router one has a default gateway that gets it to our (Lan)
router two, which in turn has a default gateway that gets it to an
(internet) router three that connects to yet another (internet) router
four., etc on out to the internet.

The clients on our LAN have default gateways that point to a few of
these routers that route traffic to our WAN locations. By having a
default gateway on these WAN routers that points to the internet
router three (above) any traffic can be routed by our WAN routers beit
directly or with ICMP redirects.

The problem is that when these remote WAN locations are shut down, the
DEFAULT GATEWAY side of these Cisco routers direct all this WAN
traffic over to internet router three. Internet router three has
static routes to the WAN locations via the LAN router two.

So we end up with a routing loop. This drains router two and router
three's resources.

How do I configure the Cisco router two so that if the WAN link isn't
down it doesn't pass that traffic off to the default gateway? I still
want unknown traffic to get ICMP redirects. Just now the WAN
locations.

To add to this, there are three LAN->WAN (not internet) routers setup
like this, which all are a part of a IGRP group.

I'm not the Networking guy - I am the guy in the router 3 portion of
this mix, where router 3 is an antivirus gateway.

Thanks;

Edwin Davidson

In article <> ,
(Edwin Davidson) wrote:

> The problem is that when these remote WAN locations are shut down, the
> DEFAULT GATEWAY side of these Cisco routers direct all this WAN
> traffic over to internet router three. Internet router three has
> static routes to the WAN locations via the LAN router two.
>
> So we end up with a routing loop. This drains router two and router
> three's resources.
>
> How do I configure the Cisco router two so that if the WAN link isn't
> down it doesn't pass that traffic off to the default gateway? I still
> want unknown traffic to get ICMP redirects. Just now the WAN
> locations.

Set up a floating static route for the WAN subnets that points to the
Null0 interface:

ip route <subnet> <mask> Serial0/1
ip route <subnet> <mask> Null0 250

As long as Serial0/1 is up, the WAN traffic will be sent to it. When
the WAN link is down the interface with shut down, and then the Null0
route will be used.

--
Barry Margolin,
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***