Help setting up a slave

[david at lewisit.com]

I get "xfer-in: transfer of 'foo.com/IN' from 9.9.9.9#53:
  failed to connect: connection refused"

What can cause this?  Can't be firewalls, I've disabled
all of that.  Must be a misconfiguration.

9.9.9.9 = external address of master
9.9.9.8 = external address of slave
10.1.1.1 = internal address of slave

My slave says:
zone "foo.com" in {
         type slave;
         masters { 9.9.9.9; };
         file "slave.foo.com";
};

My master says:
zone "foo.com" in {
         type master;
         file "db.foo.com";
         allow-transfer { 10.1.1.1; 9.9.9.8; };
};

The log of my master shows:
queries: client 9.9.9.8#2693: query: foo.com IN SOA

db.foo.com includes:
@       IN      SOA     ns1.foo.com. (
                         hostmaster.foo.com.   ; email
                         2005040100              ; serial
                         8h                      ; refresh
                         15m                     ; retry
                         30d                     ; expire
                         15m )                   ; negative cache
                 IN      NS      ns1.foo.com.
                 IN      NS      ns2.foo.com.

There is no file slave.foo.com.