[Pdns-users] Race condition during AXFR while updating slaves with two supermasters in high availability

Tony Finch dot at dotat.at
Wed Sep 18 11:44:25 UTC 2019

Guy Lee <guy at enroute.net> wrote:
> Sometimes the slaves request the AXFR from Master2 instead of Master1 who
> sent the NOTIFY. Except that Master2 hasn't updated itself yet and doesn't
> have the updated serial, so there's nothing to update on the slaves.
> Is there any way to ensure the AXFR is directed at the supermaster who sent
> the NOTIFY?

This sounds like a bug. Your situation is covered in RFC 1996 (DNS NOTIFY)
section 3.11 https://tools.ietf.org/html/rfc1996#page-4 which says the
secondary server should do what you suggest.

(Tho the description there of what RFC 1035 says doesn't match my reading:
I think it should refer to RFC 1034, and that only talks about a single
primary. RFC 5936 doesn't clarify this part of the protocol.)

f.anthony.n.finch  <dot at dotat.at>  http://dotat.at/
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