[Pdns-users] Possible AXFR Race Condition

p8x l at p8x.net
Wed Feb 23 08:29:54 UTC 2011

Hi Ton,

On 23/02/2011 4:04 PM, Ton van Rosmalen wrote:


> I'm not sure if and why a 'rediscover' would send a different
> notification but perhaps
> you could test the approach I use to see if it works for the
> bind-backend as well.
> Regards,
> Ton
Thanks for the quick reply,

I am only running the 'pdns_control rediscover' on the primary server
when a new zone is added to reread the bind config file so its away of
the new zone. After the zone exists on the master it then sends the
notify to the slave, adding the zone to the config but not actually
doing a zone transfer. It is only after the second notify that the zone
transfer actually happens (OR a server restart, a rediscover and reload
on the slave doesn't seem to fix the issue) but that causes the domain
to be added to the slave configuration twice (as it was first inserted
by the first notify).

The process I am going through for zone addition is this:

1. Add zone to super master
2. Run pdns_control rediscover on super master to re-read bind config;
the zone becomes live on the super master
3. The slave receives notify packet from super master. The slave inserts
the relevant lines into the bind slave config. The zone cannot be
queried as no zone transfer has happened yet

At stage 3 I was expecting the slave to do a zone transfer, but that
doesn't seem to happen so it takes these steps to get the zone working
on the slave

4. Restart the slave pdns server
Resend a notifcation from the master
5. Zone transfer happens and zone loads/works fine

If you would like any more information please let me know!


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