Interesting subdomain question.

[Alan Kirchhoff]

Hi,

	I have run into an interesting dns issue with a server under my
care.

	This server is primary for domain z.com. Under z.com, there exists
several subdomains for regional offices. such as:

	a.z.com
	b.z.com
	c.z.com

So far, no problem! 

But, in the zone file for z.com, subdomains a, b, and c are not officially
delegated. There are no records in z.com's zone file like this:

$origin z.com
a		86400	IN	NS ns1.a.z.com
		86400   IN	NS ns2.a.z.com
ns1.a.z.com	86400 	IN	A	1.2.3.4
ns2.a.z.com	86400 	IN	A	5.6.7.8


The primary name server for z.com is a secondary of all of the subdomains
in question. So the zone files for the subdomains are being pulled in from
the relevant subdomain name servers. 

But when I check the zone transfers on the secondaries for z.com, the
delegation information for a.z.com, b.z.com, and c.z.com is included in
z.com zone transfer. Nothing on the primary for z.com is telling it about
the subdomain delegation.