[156008] in North American Network Operators' Group
Strange Reachability Issue
daemon@ATHENA.MIT.EDU (Bryn Sadler)
Tue Sep 4 09:03:00 2012
From: Bryn Sadler <bryn.sadler@essensys.co.uk>
To: "nanog@nanog.org" <nanog@nanog.org>
Date: Tue, 4 Sep 2012 13:01:51 +0000
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
Hello all,
I was wondering if anyone might be able to share their thoughts on a strang=
e issue we're experiencing with NTT at the moment. We're AS48273 and are ad=
vertising a prefix 94.198.184.0/21 through AS 8190 (single upstream provide=
r at the moment). We've been doing this for some years now, and all has bee=
n fine. The last few days we seem to have disappeared from NTT's worldwide =
routing tables, with the exception of Europe. If we use their looking glass=
to query any NTT european router we can see the prefix, being learned via =
AS 286 then AS 8190, as expected. If we look at any other router outside of=
europe, there is simply no entry for that prefix. Elsewhere in the world w=
e seem to be fine, we're in every other network I've looked at and general =
reachability is fine.
First step was to contact the NTT NOC, and they've confirmed that there's n=
o Internal routing/config issue on their network, but that they cannot disc=
uss their peering arrangements due to NDAs. We've also picked it up with KP=
N (AS 286), who have verified that the prefix is visible throughout their n=
etwork (true), and that they are advertising it to NTT. One thing of note i=
s that Global Crossing are learning our prefix from KPN as well, and the pr=
efix is showing fine in their global tables.
We seem to be caught in the classic finger pointing scenario, but I can't g=
et my head around why the prefix is visible in NTT Europe, but not anywhere=
else, unless they have a config error somewhere on their network. We've ch=
ecked a few of the routes from AS 8190 and they are in the NTT global table=
s just fine, and at least in Europe they seem to have the same community va=
lues etc. We're still following on with NTT, but can anyone offer some wisd=
om for new avenues to pursue?
Thanks for your help,
Bryn Sadler
This message has been scanned for viruses by essensys mailcontrol
