CNAME
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... RFC-1035] records in this scenario, but in the vast majority of
cases a Canonical Name (CNAME) or Address (A) record pointer is used
to indicate the host ...
... There are two conventional approaches to creating these DNS entries.
One is to add a single CNAME record to your DNS server's
configuration, e.g.
...
... Note that in this scenario no information about ph.hivnet.fr should
exist in the DNS other than the CNAME record. For example,
ph.hivnet.fr could not contain a MX record.
...
...
It isn't a simple matter of recommending CNAMEs over A records. Each
site has it's own set of requirements ...