Re: Strange Reachability Issue

[virendra rode <virendra.rode () gmail com>]

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Hi,

On 09/04/2012 07:20 AM, Bryn Sadler wrote:
> Many thanks to Jared for jumping on this so quickly off-list, it's
> much appreciated and hopefully we're getting towards a solution
> now.
>
> Bryn
- ------------------
yup you are in good hands, sounds more like filtering related among
peers. Use can use communities to test this theory.


regards,
/virendra
> On 04/09/2012 15:12, "Jared Mauch" <jared () puck nether net> wrote:
>
> > I know a few folks from NTT have looked into this.  If someone 
> > from KPN would get in touch with Bryn I'm sure the issue could
> > be quickly resolved.
> >
> > - Jared
> >
> > On Sep 4, 2012, at 9:18 AM, Brandt, Ralph wrote:
> >
> > > I will bet that will bet that within 48 hours of you checking
> > > and posting this the problem will mysteriously go away.
> > >
> > >
> > >
> > > Ralph Brandt Mechanicsburg PA 17055
> > >
> > > -----Original Message----- From: Bryn Sadler
> > > [mailto:bryn.sadler () essensys co uk] Sent: Tuesday, September
> > > 04, 2012 9:02 AM To: nanog () nanog org Subject: Strange
> > > Reachability Issue
> > >
> > > Hello all,
> > >
> > > I was wondering if anyone might be able to share their thoughts
> > > on a strange issue we're experiencing with NTT at the moment.
> > > We're AS48273 and are advertising a prefix 94.198.184.0/21
> > > through AS 8190 (single upstream provider at the moment). We've
> > > been doing this for some years now, and all has been 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 we 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 no Internal routing/config issue on their network,
> > > but that they cannot discuss their peering arrangements due to
> > > NDAs. We've also picked it up with KPN (AS 286), who have
> > > verified that the prefix is visible throughout their network
> > > (true), and that they are advertising it to NTT. One thing of
> > > note is that Global Crossing are learning our prefix from KPN
> > > as well, and the prefix is showing fine in their global
> > > tables.
> > >
> > > We seem to be caught in the classic finger pointing scenario,
> > > but I can't get 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 checked a few of the routes
> > > from AS 8190 and they are in the NTT global tables just fine,
> > > and at least in Europe they seem to have the same community
> > > values etc. We're still following on with NTT, but can anyone
> > > offer some wisdom for new avenues to pursue?
> > >
> > > Thanks for your help,
> > >
> > > Bryn Sadler
> > >
> > >
> > > This message has been scanned for viruses by essensys
> > > mailcontrol
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