[Pdns-users] Transfer zone with lower serial from master to slave

[Nowaker]

Hey,

I work for a company that offers DNS services. Most of the customers use 
standard service, but some customers choose a plan when our servers are 
just slaves. Whenever our customer lowers the serial, we have a problem. 
We get a bug report, we have to investigate what happened, and in most 
cases the reason is the customer lowered the serial. Is it possible for 
slave PowerDNS to *ignore* this, and perform the transfer anyway? The 
ideal solution would be to get the zone transfered if their serial 
(master) doesn't equal ours (slave). After all, we are a slave, so we 
should obey what the master says, without trying to question his orders ;)

 > The only solution that really makes sense is to change the transfer
 > rules so that slaves always transfer a zone unless it is equal to the
 > master number, which is equivalent to what you propose, minus the
 > arithmetic chicanery.
 > http://marc.info/?l=pdns-dev&m=121812703211141

Has this ever been implemented in PowerDNS? (I mean "transfer a zone 
unless it is equal to the master number", not "Serial Number Arithmetic" 
that is not a case for me) Is there any switch in config file for that? 
Docs doesn't say anything about that but I just want to make sure.

> If the SOA serial number there is *higher*, the domain is retrieved and inserted into the database.
 > http://doc.powerdns.com/html/slave.html

However, the docs do say it's possible to define a custom axfrfilter 
method. Can this be used for my case? Does PowerDNS perform serial 
arithmetics and decide whether a transfer is going to be performed, or 
everything depends solely on axfrfilter?

Thanks for your answers.

-- 
Kind regards,
Damian Nowak
StratusHost
www.AtlasHost.eu