forward only recursive server doesn't forward

[Alex]

Hi,

I have a bind-9.10.3 server on fedora22 that is authoritative for a
few domains and their corresponding IP ranges. I'd like to set up
another domain server (rbldnsd) on a host in one of those domains as a
forward-only server.

The problem appears to be that the queries from the local box to the
subdomain being managed by the rbldnsd server are being answered by
the local bind instead of being sent to the remote machine running
rbldnsd.

In other words, I believe the issue is that the host is already
authoritative for the reverse zone, so there would be no reason for it
to forward these queries to another system.

Here are the relevant sections of my named.conf:

// spam IP entries
zone "scann.example.com" {
        type forward;
        forwarders { 66.104.104.66; };
};

// zone info for 66.104.104.96/28
zone "96/28.104.104.66.in-addr.arpa" {
        type slave;
        file "slaves/db.104.104.66";
        masters { 64.1.1.3; };
        allow-query { any; };
        allow-transfer { trusted; };
};

Queries for abc.com.scann.example.com fail with NXDOMAIN. Log entries
are similar to this:

19-Oct-2016 21:22:39.846 queries: client 127.0.0.1#41809
(abc.com.scann.example.com): query: abc.com.scann.example.com IN A +
(127.0.0.1)

I set up the reverse zone a long time ago, and I don't think the "zone
96/28.104.104.66.in-addr.arpa" is completely correct, but it appears
to work. I'm not sure if that's related to the problem, but would
appreciate advice there.

Thanks,
Alex