[Pdns-users] PowerDNS authoritative: AXFR ignored when SOA serial wraps

Jan-Piet Mens jpmens.dns at gmail.com
Thu Mar 17 09:31:08 UTC 2011

Good morning,

there seems to be a glitch with PDNS 3.0 build 2067 here :-) Running as
a slave to a BIND master.

When a DNS update on the master causes the SOA serial to wrap from
(2^32)-1 back to 1, PowerDNS refuses to transfer the zone because the
master's serial number is lower than that which it (pdns) has.

Reproduce as follows:

1. BIND master zone with SOA serial = 4294967295
2. PDNS transfers the zone correctly and it too has a serial = 4294967295
3. Update BIND master (ddns):
        a. BIND wraps the serial to 1
        b. PDNS log says:
                Received serial number update for 1 zones, had 0 timeouts
                Domain b.aa more recent than master, our serial
                4294967295 > their serial 1

        Effect is that zone is not transferred.

4. A second update to BIND master:
        a. BIND sets the serial to 2
        b. PDNS reacts same way as in 3.b

PowerDNS' saying "... more recent than master..." doesn't take into
account that the serial can wrap back to 1 upon "unsigned-int-overflow".

Best regards,


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