Best implementation of many zonfiles containing the same info (to avoid duplicate IP-nr)

[news at teknologia.com]

When handling a lot of domain names you want to avoid the same IP-nr in
many zonefiles, but how is best way of doing it?


Let's say we have 200 domain names, one zonefile for each. All domains
points to same servers so all zonefiles are more or less equal except
for the SOA-record-line and the A-record for the root level of the
domain name.
Our main server is www5.ourcompany.com so all zonefiles uses CNAME for
all subdomains and stuff, pointing to www5.oucompany.com. (MX and NS
points to other servers as well).

We would like to get around the problem of having the following line in
each zonefile:
domainname.com          IN      A            X.X.X.X
First thought was to put CNAME even here but I know that is not
allowed.

I simply wants to avoid IP-number in every zonefile because of the work
involved every time the IP-nr change of the main server.

Any suggestion to do this? Of course it must agree with RFC regulations
and follow bind rules. 

Best regards
Martin Rådbo