[42710] in North American Network Operators' Group
RE: looping traceroutes
daemon@ATHENA.MIT.EDU (Hire, Ejay)
Wed Sep 19 11:52:42 2001
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From: "Hire, Ejay" <Ejay.Hire@Broadslate.net>
To: nanog@merit.edu
Date: Wed, 19 Sep 2001 11:51:35 -0400
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This behavior would occur if the traffic was routed to a loopback interface.
-----Original Message-----
From: Leo Bicknell [mailto:bicknell@ufp.org]
Sent: Wednesday, September 19, 2001 8:09 AM
To: nanog@merit.edu
Subject: Re: looping traceroutes
On Wed, Sep 19, 2001 at 12:40:51AM -0700, Ratul Mahajan wrote:
> Do you think that it can be a real persistent routing loop (data packets
> would actually shuttle between the two interfaces) as against some
> wierdness because of traceroute?
I'd tell you a story, but it would make all of nanog cringe. Put
simply, I know of at least one medium size regional network who
when they couldn't make "bgp work" decided to implement a series
of scripts that logged into all routers and installed statics to
make things work.
Let me just tell you, after a few short weeks of adding and removing
(and missing) such routes there were loops all over the place, many
of which are probably still there. :-(
There are a number of ways long lived loops can occur. I believe
others have pointed out some other methods.
--
Leo Bicknell - bicknell@ufp.org
Systems Engineer - Internetworking Engineer - CCIE 3440
Read TMBG List - tmbg-list-request@tmbg.org, www.tmbg.org
