a question about NS entries

[johnny at n0sq.net]

When creating a primary DNS, do I need to create a NS record in my zone file 
for the secondary DNS or is it only necessary to modify /etc/named.conf to 
allow transfers to the secondary (slave) DNS? Or are both required. My 
understanding of zone files is that only entries for my domain are 
necessary.

Mandrake Linux 9.0, Bind 9