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RE: Routing loop [7:84050] posted 02/09/2004
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As someone else already mentioned, the route must originate from
somewhere, and a router isn't going to originate a prefix that doesn't
exist. If you're seeing it, then some router somewhere is advertising
it. Try doing a "clear ip route *" on your routers and see if that
helps. You've probably already done this, though.

What model are these routers? And what version of IOS are you running?
I'm beginning to wonder if you're seeing a bug, and a directly connected
route that used to exist is still being advertised.


>>> "TorZI-I/Brian Dunbar"  2/9/04
11:08:01 AM >>>
If the Subnet existed somewhere wouldn't one of the routers show the
Each of these routers (in production) show each other as the source of
route when I do
show ip route x.x.x.x EIGRP learns it from router A go to router A and
show ip route x.x.x.x it learns from another of the 6 eventually it
will hit
back to the first router.

-----Original Message-----
From: nobody@xxxxxxxxxxxxxx [mailto:nobody@xxxxxxxxxxxxxx]On Behalf Of
John Neiberger
Sent: February 9, 2004 12:54 PM
To: cisco@xxxxxxxxxxxxxx 
Subject: Re: Routing loop [7:84050]

>>>> TorZI-I/Brian Dunbar 2/9/04 10:48:58 AM >>>
>I have an unusual routing loop that is hard to get rid of. The route
>learned by EIGRP from a circle of about 6 routers each refers to the
>as the source of the route.
>I put a static route on the central router to NULL0 and all 6 routers
>learned the route. Then I delete the null route 30 minutes later and
>route loop reappears. The routing loop is to an invalid subnet that
>exist. May of existed at one point. None of the 6 routers refer to
>source for the route.
>Any ideas?

I think the subnet must exist or the originating router wouldn't keep
advertising it. Unless you're running into a really strange bug, a
router is
not going to originate a completely fictitious route. Can you give us
more details? Is this a lab or production environment?

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