We have two Win2k3 dns servers, not on the same network or same location.
Primary DNS has all of the zones created and functioning, running as Primary non-AD integrated zones. The Secondary DNS server is listed on all of the Name Server tabs for all of the zones, Zone Transfers are enabled for servers in the Name Servers, and dynamic updates are allowed.
Some zones are failing to transfer to the Secondary server. The two event id's we are seeing for this are
Event Id 6525:
A zone transfer request for the secondary zone failedtransferzone.com was refused by the master DNS server at [ip]. Check the zone at the master server [ip] to verify that zone transfer is enabled to this server. To do so, use the DNS console, and select master server [ip] as the applicable server, then in secondary zone failedtransferzone.com Properties, view the settings on the Zone Transfers tab. Based on the settings you choose, make any configuration adjustments there (or possibly in the Name Servers tab) so that a zone transfer can be made to this server.
And Event Id 6527:
Zone failedtrasnferzone.com expired before it could obtain a successful zone transfer or update from a master server acting as its source for the zone. The zone has been shut down.
Some zones are able to transfer from the Primary to the Secondary, but there are a handful that will not. Have tried to deleted/recreate the zones on the Secondary server, transfer/reload from the Master, with no success.
The registry keys for the xferthrottling do not exist on either server.
Again, zone transfers are allowed for these zones, with the Secondary being listed in the Name Servers tab.