I wonder how you guys keep the secondary DNS in sync if Froxlor creates zone entries for a (hidden) primary DNS. There's still a problem for me, that new domains needs to be added by hand to secondary. This of course leads to inconsistencies. Someone a clue how to do that better?

why add new domains by hand? There are lots of synchronization tools like "rsync" which you can setup to sync your nameservers

I transfer the zones every 3 hours to my slave via cron job and then reload bind.

But you can also use a powerdns supermaster setup. Work with bind master and powerdns slave

http://www.tummy.com/journals/entries/jafo_20090321_135746

EleRas is currently working on a complete rewrite of this, i'll tell him to consider this

sorry to get up old posts, but i can't see where this has been solved...?

it has not. There are several tickets in our bugtracker regarding DNS. Follow or add information to them if you like.