3.1.1. The Zone Section is checked to see that there is exactly one RR therein and that the RR's ZTYPE is SOA, else signal FORMERR to the requestor. Next, the ZNAME and ZCLASS are checked to see if the zone so named is one of this server's authority zones, else signal NOTAUTH to the requestor. If the server is a zone slave, the request will be forwarded toward the primary master.
3.1.2. Pseudocode For Zone Section Processing
if (zcount != 1 || ztype != SOA) return (FORMERR) if (zone_type(zname, zclass) == SLAVE) return forward() if (zone_type(zname, zclass) == MASTER) return update() return (NOTAUTH)
Sections 3.2 through 3.8 describe the primary master's behaviour, whereas Section 6 describes a forwarder's behaviour.