[Pdns-users] Some PowerDNS Recursor oddities

[Darren Gamble]

Good day,

We've been testing out the PowerDNS Recursor daemon (3.1pre2, installed via the i386 Linux rpm), and just wanted to report on a couple of minor problems.  We're otherwise quite happy with how well the software held up in the lab.

We noted that, in some situations, the daemon doesn't update its TTL values for a record.  For example, for the zone "truespace.ca" that we made some changes to for this testing, you'll note the CIRA (.ca) servers have 2D TTL values for the ns1 and ns2 NS records, but the TTL on the authoritative servers themselves is 1H.  The first query for these records returns the 1H TTL, but, subsequent queries show that the 2D TTL values are the ones cached.  We added a third NS record (ns3) to help illustrate this.

We am not sure if this behavior is still considered compliant, but, it would certainly generate complaints from hosters who lowered their TTLs for a migration, among other situations.  PowerDNS is the only DNS caching software we have tried that behaves in this way (unless you count BIND's, MaraDNS' and Network Registrar's capabilities to avoid indefinitely caching an NS record).  Comments?  Working as designed, or is this an issue?

Also, we noted that when the daemon is started with "fork", the init script is unable to stop the daemon.  This appears to be because the daemon always calls rec_control using the default socket, but, the sockets are actually named pdns_recursor.controlsocket.<pid> for the two processes when forked.  We am not sure if this is best resolved by changing the init script or changing rec_control.

Please let us know!  And, good job with the product!

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Darren Gamble
Planner, Regional Services
Shaw Cablesystems GP
630 - 3rd Avenue SW
Calgary, Alberta, Canada
T2P 4L4
(403) 781-4948