Re: Tips for DNS zone administration

[Robert Elz <kre@munnari.OZ.AU>]

    Date:        Sat, 21 Apr 2001 17:28:54 +0200 (CEST)
    From:        Mats Dufberg <dufberg@nic-se.se>
    Message-ID:  <Pine.BSF.4.30.0104211713550.1551-100000@spider.nic-se.se>

  | On Sat, 21 Apr 2001, Sam Trenholme wrote:
  | 
  | >      * Never have the same computer names used for NS records for your
  | >        domain be used for anything else, such as MX records or CNAME
  | >        records.
  | 
  | I know that CNAME must not be combined with MX or NS in the same node, but
  | what combinations of NS and MX are bad?

There's nothing illegal about having NS records use the same names as
anything else (including the name of the domain itself, as Randy showed
in his reply) - except that of a CNAME of course.

On the other hand, I agree with the advice, it turns out that updating the
value of an NS record can be hard (it can appear as glue in all kinds of
weird places) and can sometimes take a long time to achieve.   It can often
be better to simply abandon an old NS name (value of the RDATA of an NS
record) and invent a new one.   That's pretty easy if the name is used for
nothing other than the NS record, much harder if it is also used for all
kinds of other purposes (expecially when it is used for human visible 
purposes).

This may not be as difficult now as it used to be (changes in nameserver
habbits) - but I know that I renumbered a whole lot of a campus just to
avoid changing munnari.oz.au's IP address(es) when it moved on the internal
network (a few years ago now) - just to avoid these problems.  (If I was
setting things up now knowing what I now know, rather than what I knew 15
years ago, I never would have used that name in NS records).

kre