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Path: utzoo!attcan!uunet!samsung!spool.mu.edu!sdd.hp.com!news.cs.indiana.edu!ux1.cso.uiuc.edu!mp.cs.niu.edu!rickert
From: rickert@mp.cs.niu.edu (Neil Rickert)
Newsgroups: comp.unix.internals,comp.unix.ultrix,comp.unix.questions
Subject: Re: additional definition for domainname
Keywords: name server domain
Message-ID: <1991Feb6.133455.9226@mp.cs.niu.edu>
Date: 6 Feb 91 13:34:55 GMT
References: <2836@bimacs.BITNET>
Organization: Northern Illinois University
Lines: 39

In article <2836@bimacs.BITNET> yedidya@bimacs.BITNET (Yedidya Israel) writes:
>Consider the following defintions for domainnames math.purdue.edu and
>cs.cms.edu.
>
>[bimacs] yedidya 137 : host -a math.purdue.edu.
>[ ... ]
>math.purdue.edu 86333 IN        CNAME   gauss.math.purdue.edu
>[ ... ]
>
>[bimacs] yedidya 114 : host -a cs.cmu.edu.
>[ ... ]
>cs.cmu.edu      110243 IN       A       128.2.222.173
>[ ... ]
>
>1) Is it legal to define my domain name to be A/CNAME/MX ? Which is
>better ?
>
 I am not sure that legality is involved.  The effect of a CNAME record is
that the real name is actually substituted for the orignal name.  Providing
an A-record allows some software to access the name without translation
of the name.  Many domains are set up with several different names having
the same A-record.  It helps deal with obsolete email software which cannot
read MX records.  It enables hosts with such software to still find you.
There are also times when a host changes name and cannot use a CNAME record
for aliasing because it wants to retain an MX record or SOA record under the
old name.  An A-record is thus provided so that the host is still
accessible under the old name.

>2) Is it legal to have more that one A record for one host ?

 If you have more than one network interface you have multiple addresses,
so you should have multiple A-records.


-- 
=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=
  Neil W. Rickert, Computer Science               <rickert@cs.niu.edu>
  Northern Illinois Univ.
  DeKalb, IL 60115                                   +1-815-753-6940


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