CNAME VS A

[Barry Margolin]

In article <5DEF109335DAD111B05F00A0C9DDFC023398B4 at ROCHS2>,
Scott.Wiseman <scott.wiseman at realestatenet.com> wrote:
>what is the difference?
> 
>bigt.movie.edu    IN    A    192.168.1.1
>bigdah.movie.edu    IN CNAME bigt.movie.edu
> 
>VS
> 
>bigdah.movie.edu    IN    A    192.168.1.1

There are some situations where you can't use the first version.  You can't
do:

movie.edu.  IN MX 10 bigdah.movie.edu.

or:

movie.edu.  IN NS bigdah.movie.edu.

because MX and NS records are required to point to A records, not CNAME
records.  Also, you can't do:

bigdah.movie.edu.  IN MX 10 mail.movie.edu.

because this would violate the "CNAME and other data" prohibition.

-- 
Barry Margolin, barmar at genuity.net
Genuity, Burlington, MA
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