Strange log file entries

[Jim Reid]

>>>>> "Andy" == Andy Frog <me at privacy.net> writes:

    Andy> I was looking at the /var/log/messages and found the
    Andy> following entry continually being added to my log file:

    Andy> Nov 21 09:18:12 mysite named[343]: client 4.15.157.4#2726: update denied
    Andy> What does that mean and how do I put a stop to it?

It means what it says. IP address 4.15.157.4 sent a dynamic update
request (from port 2726) and your server refused to process it. The
way to put a stop to it depends. If you want this host to be permitted
to send dynamic update requests, put an allow-update clause at the
appropriate place in named.conf. If you don't, find out what's
generating the update requests on that host - probably some W2K box -
and stop them. Enabling dynamic DNS is fraught with security problems:
allowed hosts can pretty much add or remove whatever they like from
a zone. And it's no longer possible to manually maintain a zone file
once the zone is subject to dynamic updates.

    Andy> Also, I get the following line once in a while.  What does
    Andy> it mean?

    Andy> Nov 21 09:18:07 mysite named[343]: dynamic update failed: 'RRset exists (value dependent)' prerequisite not satisfied (NXRRSET)

This message means what it says too. The dynamic update request failed
because a prerequisite condition - that some name or group of names
(RRset in DNS jargon) existed - did not hold. An NXRRSET error - no
such RRset - was returned to the client making the request.