[Pdns-users] IXFR confuses dig, Godaddy

Pierre Beck pbeck at videobuster.de
Fri Dec 27 19:50:40 UTC 2013


PowerDNS sends AXFR in three packets: SOA, RRs, SOA. This is fine with
AXFR requests, but leads to problems with IXFR requests. One problem is
that a standalone SOA with matching serial is considered a complete
answer in IXFR. Dig closes the connection but PowerDNS keeps sending
data which will be discarded by OS (answered with TCP RST). Just cosmetics.

Another more serious problem occurs when serials don't match: dig keeps
waiting for further data after the second SOA, which is actually a bug
in dig, not in PowerDNS.

dig: ;; communications error to end of file
pdns: TCP Connection Thread died because of STL error: Timeout reading data

That shouldn't be a problem of PowerDNS, but it already affects
compatibility, e.g. with Godaddy nameservers (maybe they used dig / BIND
as a reference for their implementation).

Anyways, wrapping the response in one packet instead of three would
likely resolve both issues (using a MS DNS, which creates only one
packet, doesn't confuse dig). Should I file this as a bug?


Pierre Beck

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