nanog mailing list archives

Re: Centurylink having a bad morning?


From: Jason Kuehl <jason.w.kuehl () gmail com>
Date: Mon, 31 Aug 2020 11:43:11 -0400

At the end of the day, the business needs to besides to take that cost. All
you can do is document, and talk about the risks.

Save that email for that "I told you so moment"

On Mon, Aug 31, 2020 at 10:50 AM Mike Bolitho <mikebolitho () gmail com> wrote:

That's all we can do. Thankfully I work for an org that understands this
and has *at least* two fully redundant circuits. Sometimes a third
smaller carrier if we can prove that it is diverse, but that isn't the case
very often.

- Mike Bolitho


On Mon, Aug 31, 2020 at 7:35 AM Tomas Lynch <tomas.lynch () gmail com> wrote:

Maybe we are idealizing these so-called tier-1 carriers and we, tier-ns,
should treat them as what they really are: another AS. Accept that they are
going to fail and do our best to mitigate the impact on our own networks,
i.e. more peering.

On Mon, Aug 31, 2020 at 9:54 AM Martijn Schmidt via NANOG <
nanog () nanog org> wrote:

At this point you don't even know whether it's a human error (example:
generating a flowspec rule for port TCP/179), a filtering issue (example:
accepting a flowspec rule for port TCP/179), or a software issue (example:
certain flowspec update crashes the BGP daemon). And in the third scenario
I think that at least some portion of the blame shifts from the carrier to
its vendors, assuming the thing that crashed was not a home-grown BGP
implementation.

With the route optimizer incidents - because let's face it, Honest
Networker is on the money as usual
https://honestnetworker.net/2020/08/06/as10990-routing/ - there is
really no excuse for any tier-1 carrier, they should at the very least have
strict prefix-list based filtering in place for customer-facing EBGP
sessions. In those cases it's much easier to state who's not taking care of
their proverbial lawn.

Best regards,
Martijn

On 8/31/20 3:25 PM, Tom Beecher wrote:


https://blog.cloudflare.com/analysis-of-todays-centurylink-level-3-outage/


I definitely found Mr. Prince's writing about yesterday's events
fascinating.

Verizon makes a mistake with BGP filters that allows a secondary mistake
from leaked "optimizer" routes to propagate, and Mr. Prince takes every
opportunity to lob large chunks of granite about how terrible they are.

L3 allows an erroneous flowspec announcement to cause massive global
connectivity issues, and Mr. Prince shrugs and says "Incidents happen."





On Mon, Aug 31, 2020 at 1:15 AM Hank Nussbacher <hank () interall co il>
wrote:

On 30/08/2020 20:08, Baldur Norddahl wrote:


https://blog.cloudflare.com/analysis-of-todays-centurylink-level-3-outage/

Sounds like Flowspec possibly blocking tcp/179 might be the cause.

But that is Cloudflare speculation.

Regards,
Hank
Caveat: The views expressed above are solely my own and do not express
the views or opinions of my employer

An outage is what it is. I am not worried about outages. We have
multiple transits to deal with that.

It is the keep announcing prefixes after withdrawal from peers and
customers that is the huge problem here. That is killing all the effort and
money I put into having redundancy. It is sabotage of my network after I
cut the ties. I do not want to be a customer at an outlet who has a system
that will do that. Luckily we do not currently have a contract and now they
will have to convince me it is safe for me to make a contract with them. If
that is impossible I guess I won't be getting a contract with them.

But I disagree in that it would be impossible. They need to make a good
report telling exactly what went wrong and how they changed the design, so
something like this can not happen again. The basic design of BGP is such
that this should not happen easily if at all. They did something unwise.
Did they make a route reflector based on a database or something?

Regards,

Baldur

On Sun, Aug 30, 2020 at 5:13 PM Mike Bolitho <mikebolitho () gmail com>
wrote:

Exactly. And asking that they somehow prove this won't happen again is
impossible.

- Mike Bolitho

On Sun, Aug 30, 2020, 8:10 AM Drew Weaver <drew.weaver () thenap com>
wrote:

I’m not defending them but I am sure it isn’t intentional.



*From:* NANOG <nanog-bounces+drew.weaver=thenap.com () nanog org> *On
Behalf Of *Baldur Norddahl
*Sent:* Sunday, August 30, 2020 9:28 AM
*To:* nanog () nanog org
*Subject:* Re: Centurylink having a bad morning?



How is that acceptable behaviour? I shall remember never to make a
contract with these guys until they can prove that they won't advertise my
prefixes after I pull them. Under any circumstances.



søn. 30. aug. 2020 15.14 skrev Joseph Jenkins <
joe () breathe-underwater com>:

Finally got through on their support line and spoke to level1. The
only thing the tech could say was it was an issue with BGP route reflectors
and it started about 3am(pacific). They were still trying to isolate the
issue. I've tried failing over my circuits and no go, the traffic just dies
as L3 won't stop advertising my routes.



On Sun, Aug 30, 2020 at 5:21 AM Drew Weaver via NANOG <
nanog () nanog org> wrote:

Hello,



Woke up this morning to a bunch of reports of issues with
connectivity had to shut down some Level3/CTL connections to get it to
return to normal.



As of right now their support portal won’t load:
https://www.centurylink.com/business/login/



Just wondering what others are seeing.







-- 
Sincerely,

Jason W Kuehl
Cell 920-419-8983
jason.w.kuehl () gmail com

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