Combined master + forward zone

[Petteri Heinonen]

Hello all. I have been struggling with a seeming simple Bind related 
problem. My main goal would be to have dynamically added RRs served by 
different server than the normal statically configured RRs. Essentially, 
the zone's RRs would be divided on two Bind servers. Here is the setup I 
would like to achieve:

- Primary master for our zone, serving the statically configured DNS 
entries. This server would not be used directly by the clients. This 
server would not accept DDNS update requests either.
- Second server for the same zone as the first one. This server would 
then accept DDNS update requests, and store the entries for those locally.

Now, upon a normal DNS query, the second server would need to work as 
follows:

1. Check if the name queries exists locally. If yes (in the case the 
name has been dynamically added), send the response to the client.
2. If not, forward the query to Primary master of the zone.
3. If not found there either, response with NXDOMAIN.

What would be simply needed is some kind of "hybrid" master+forward type 
of zone: if RR is found locally response normally, and if not found, 
forward to another server. However, I haven't found a way to do this 
with Bind. Any suggestions how this could be achieved?

Regards, Petteri Heinonen