nanog mailing list archives
Re: DNS pulling BGP routes?
From: Christopher Morrow <morrowc.lists () gmail com>
Date: Fri, 8 Oct 2021 13:03:52 -0400
(I'm going to hate myself in the morning, but) On Fri, Oct 8, 2021 at 10:22 AM Masataka Ohta < mohta () necom830 hpcl titech ac jp> wrote:
William Herrin wrote: https://engineering.fb.com/2021/10/05/networking-traffic/outage-details/ our DNS servers disable those BGP advertisements if they themselves can not speak to our data centers The end result was that our DNS servers became unreachable even though they were still operational. means their DNS servers were serving the zone, even after they recognize their zone data were too old, that is, expired.
that's not what this means. I think Mr. Petach previously described this, but: 1) dns server in pop serves some content (ttls aren't important right now) 2) dns server uses some quagga/gated/bird/etc to announce locally: "Hey, foo/32 here!" (imagine this triggers an 'aggregate route' or 'network statement' (pick your vendor solution) to appear in the global table) 3) dns server also 'ping backend server set' 4) when 3 fails for X period of time 'tell quagga/bird/etc to stop announcing the /32' then the local pop no longer sources the aggregate (/24 or /23 or whatever)... so traffic SHOULD (externally) flow toward another copy of the /23 or /24 or whatever... there's not a lot of magic here... and it's not about the zone data really at all.
Current thread:
- Re: DNS pulling BGP routes?, (continued)
- Re: DNS pulling BGP routes? Masataka Ohta (Oct 07)
- Re: DNS pulling BGP routes? William Herrin (Oct 07)
- Re: DNS pulling BGP routes? Masataka Ohta (Oct 07)
- Re: DNS pulling BGP routes? Sabri Berisha (Oct 07)
- Re: DNS pulling BGP routes? Mark Tinka (Oct 07)
- Re: DNS pulling BGP routes? Masataka Ohta (Oct 08)
- Re: DNS pulling BGP routes? Tom Beecher (Oct 08)
- Re: DNS pulling BGP routes? Carsten Bormann (Oct 08)
- Re: DNS pulling BGP routes? William Herrin (Oct 08)
- Re: DNS pulling BGP routes? Masataka Ohta (Oct 08)
- Re: DNS pulling BGP routes? Christopher Morrow (Oct 08)
- Re: DNS pulling BGP routes? Masataka Ohta (Oct 09)
- Re: DNS pulling BGP routes? Bill Woodcock (Oct 09)
- Re: DNS pulling BGP routes? Masataka Ohta (Oct 09)
- Re: DNS pulling BGP routes? Christopher Morrow (Oct 11)
- Re: DNS pulling BGP routes? Matthew Petach (Oct 11)
- Re: DNS pulling BGP routes? Masataka Ohta (Oct 12)
- Re: DNS pulling BGP routes? Matthew Petach (Oct 11)
- Re: DNS pulling BGP routes? Masataka Ohta (Oct 12)
- Re: DNS pulling BGP routes? Matthew Petach (Oct 12)
- Re: DNS pulling BGP routes? Masataka Ohta (Oct 13)