nanog mailing list archives

Re: validating reachability via an ISP


From: Andy Litzinger <andy.litzinger.lists () gmail com>
Date: Thu, 5 Apr 2018 10:30:58 -0700

Hi Andy,
  The root cause was they regional ISP was failing to advertise my prefix
due to a mistake in their export policy.  While I'm glad we were able to
figure out the issue I'm generally more interested in figuring out a way
that I can programmatically monitor that my ISPs are providing me with good
reachability, even when their route isn't necessarily the best/installed
route to me.

I do have route objects defined in an IRR for this prefix. Perhaps you
wouldn't mind explaining to me how route-server or ISP operators generally
validate route-objects before accepting routes?  Especially in the case
where I'm not peering with your route server but my ISP is.  Do you query
the IRR DB to recurse from the ISP AS to my AS and validate route objects
there?

thanks!
-andy



On Thu, Apr 5, 2018 at 12:49 AM, Andy Davidson <andy () nosignal org> wrote:






On 29/03/2018, 00:22, Andy Litzinger <andy.litzinger.lists () gmail com>
wrote:

The root cause is that the our prefix is not being adequately
re-distributed globally by the regional ISP.  This is unexpected and we
are
working through this with them now.

Hi, Andy —

Are you failing to advertise it, or are they filtering it on ingress, or
are they failing to send it to their other peers?

One configuration mishap which is starting to come along more and more
partial or poor reachability caused by route objects which are not
correctly published in the IRRDB. It is going to be essential to make sure
that you have properly recorded IRR route objects in, for instance, RADB.
More BGP speakers properly filter their peers using information that is
published there.  Avoid future reachability problems by checking this today!

Yours,
A friendly route-server operator with strict filtering

-a



--
Andy Davidson            Asteroid International BV
https://www.asteroidhq.com    @asteroidhq   @andyd
--------------------------------------------------
Local interconnection.          Where you need it.




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