nanog mailing list archives
Re: someone is using my AS number
From: Jon Lewis <jlewis () lewis org>
Date: Sat, 15 Jun 2019 09:19:23 -0400 (EDT)
On Sat, 15 Jun 2019, Filip Hruska wrote:
In other words, if I have an upstream that uses 6939 for transit, I'm free to permanently prepend 6939 to stop propagation to that network? Isn't using a community that says "do not export to 6939" a better and much cleaner solution?
Sure, unless/until that doesn't work. In the case I recall where I used as-path poisoning, we were multihomed to two NSPs. For TE purposes, we'd been advertising a couple of more specifics to NSP1 with community strings to limit propagation. One day, NSP2 went from being a peer of NSP1 to a customer of NSP1. Generally, if a network even has customer usable propagation limiting community support, it's only applicable to their peers, not customers. So, when the peering relationship between NSP1 & NSP2 changed, our TE became less effective because NSP2 started receiving the more specifics from NSP1. The fix was to add NSP2's AS to the more specifics sent to NSP1...and to eventually get another transit provider.
You will have to explain that to SpamHaus and other organizations who are in the business (literally) of blacklisting all upstreams of "rogue" networks.
I think they have enough clue to notice "screwy as-paths". ---------------------------------------------------------------------- Jon Lewis, MCP :) | I route | therefore you are _________ http://www.lewis.org/~jlewis/pgp for PGP public key_________
Current thread:
- someone is using my AS number Philip Lavine via NANOG (Jun 12)
- Re: someone is using my AS number David Guo via NANOG (Jun 12)
- Re: someone is using my AS number Joe Provo (Jun 12)
- Re: someone is using my AS number Joe Abley (Jun 13)
- Re: someone is using my AS number Job Snijders (Jun 13)
- Re: someone is using my AS number Joe Abley (Jun 13)
- Re: someone is using my AS number Owen DeLong (Jun 15)
- Re: someone is using my AS number Filip Hruska (Jun 15)
- Re: someone is using my AS number Jon Lewis (Jun 15)
- Re: someone is using my AS number Job Snijders (Jun 15)
- Re: someone is using my AS number Jon Lewis (Jun 15)
- Re: someone is using my AS number Job Snijders (Jun 15)
- Re: someone is using my AS number Jon Lewis (Jun 15)
- Re: someone is using my AS number Joe Provo (Jun 12)
- Re: someone is using my AS number David Guo via NANOG (Jun 12)
- Re: someone is using my AS number Owen DeLong (Jun 15)
- Re: someone is using my AS number Warren Kumari (Jun 13)
- Re: someone is using my AS number Job Snijders (Jun 13)
- Re: someone is using my AS number Jared Mauch (Jun 13)
- Re: someone is using my AS number Jon Lewis (Jun 13)
- Re: someone is using my AS number Filip Hruska (Jun 13)