SUMMARY: Several A Records per *IP Number*?

From: Jochen Bern (bern@penthesilea.uni-trier.de)
Date: Wed Nov 13 1996 - 17:16:22 CST


I wrote:
> I have a Situation in which I'ld like to have our DNS have two
> A Records for the same IP#. (Repeat: Same *Number*, not Name!)
> I'ld like to know what Problems this could cause - there are
> other Ways to achieve what I want, but they all cause undesirable
> Effects, so I'm looking for the least-Trouble Solution. :-}

Clarification (since I've been misunderstood by some): What I mean is
name1 IN A 1.2.3.4
name2 IN A 1.2.3.4
(plus optionally other Records for name1 and name2, but no more A Records).

Answers:
1) That's perfectly legal, and gets done in a Lot of Places.
2) There will be only one PTR Record, though, so if some other Host
   wants to doublecheck the DNS Data of the second Hostname, it will
   suspect a hacked Host. [I don't expect such Checks to be done in
   any Context where the second Name is used, except Email, and that
   will be taken Care of by MXes and sendmail.cw and such.]
3) Better get a recent named Version before doing such Tricks. [We
   run BIND 4.9.x.]
4) What you want is a CNAME. [I *have* CNAMEs right now. My Problem is
   that sendmail 8.x running wherever on the World wants to replace
   a CNAME by the real Hostname, and promptly ruins the Addresses.]

Thanks to (preliminary List ;-) :

Arthur Darren Dunham <add@is.rice.edu>
Stephen Harris <sweh@mpn.com>
Frank Pardo <fpardo@tisny.com>
Dan Pritts <danno@fv.com>
Rick Berube <spreb@fozzie.cha.tva.gov>
Reto Lichtensteiger <rali@meitca.com>
Milt Webb <milt@iqsc.com>

Regards,
                                                                J. Bern

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