client 1.2.3.4#56789: update 'sampledomain.com/IN' denied

[Johan Kuuse]

I was using BIND 9.1.0 until recently, now I am using BIND 9.2.1.
The upgrade implies that the log file is filling up with the message

client 1.2.3.4#56789: update 'sampledomain.com/IN' denied

for various domains (we are an ISP managing about 250 domains).
I have seen on this list that one solution to this problem is to fix the
client (normally Win2k).
In our case the problem cannot be solved that way (too many clients).

I think I found a solution here:
http://www.acmebw.com/askmrdns/archive.php?category=83&question=603
which says:
"Change the MNAME field of your SOA record to "localhost" and include a
"localhost" in the zone that points to 127.0.0.1."

I still have some doubts.
If I change the MNAME field to "localhost" for zone "sampledomain.com",
should the host "localhost.sampledomain.com" be used as 127.0.0.1?
And what happens with the slave server if the the MNAME points to
"localhost"?
(I thought that the MNAME always should point to the master DNS server?)

Any comment to this approach, or any other "server-side" solution is
appreciated.

Regards,
Johan Kuuse
kuuse at redantigua.com

Zone file as I guess it would look like:
----------------------------------------------------------------------------
-------
$ORIGIN .
$TTL 86400      ; 1 day
sampledomain.com.               IN SOA  localhost
postmaster.sampledomain.com. (
                                2002070100 ; serial
                                3600       ; refresh (1 hour)
                                1200       ; retry (20 minutes)
                                1296000    ; expire (2 weeks 1 day)
                                86400      ; minimum (1 day)
                                )
                        NS      ns.me-the-isp.com.
                        NS      ns2.me-the-isp.com.
                        A       1.2.3.5
$ORIGIN sampledomain.com.
localhost             A       127.0.0.1
mail                    A       1.2.3.4
www                  A       1.2.3.5
----------------------------------------------------------------------------
-------