From: kym blair (kymblair@xxxxxxxxxxx)
Date: Wed Aug 07 2002 - 09:44:27 GMT-3
Add an outbound access-list at your premise router so packets that are
sourced internally and destined to an internal addresses cannot leave your
network. How can this happen? One of your internal networks is down and
other people (e.g., your network monitoring station) try to ping or trace to
it. Since that network is down, the packet heads for the default gateway
(like a river flowing to the open sea). If you're advertising your internal
networks via BGP, then the ISP will send the packet back to you. When you
get the packet back, you send it out toward your default gateway again ...
etc until TTL expires. Instead of an outbound access-list, you could apply
an inbound to deny any packet sourced from an internal address. Or statics
to Null0 could be installed.
HTH, Kym
>From: Hansang Bae <hbae@nyc.rr.com>
>Reply-To: Hansang Bae <hbae@nyc.rr.com>
>To: ccielab@groupstudy.com
>Subject: Re: How to detect routing loop
>Date: Tue, 06 Aug 2002 23:16:25 -0400
>
>At 01:50 AM 8/7/2002 +0000, Gordan Chan wrote:
> >I am thinking how to detect route loop.
> >Could someone share the checklist/method on the detection and how to
>prevent it?
>
>
>
>
>Use traceroute or wait for people to start calling you?!?
>
>Some tips to avoid routing loops
>
>1) If you redistribute, use a route-map (or something similiar) to avoid
>route feedbacks.
>
>2) If you have a summarized routes, make sure you route to null0 so that
>you don't have a loop.
>
>hsb
This archive was generated by hypermail 2.1.4 : Sat Sep 07 2002 - 19:48:18 GMT-3