[UPHPU] CNAME or A for MX value

[Lonnie Olson]

On Thu, Jul 3, 2008 at 3:39 PM, Joseph Scott <joseph at randomnetworks.com> wrote:
> It's been a long time since I've had to look it up, but the rule had always
> been that MX records do NOT point to CNAMEs.

Joseph is right here.  MX records must not point to a CNAME but to an A record.

Good example:
example.com.    MX    10 mail.example.com.
mail.example.com.    A    123.123.123.123

Bad example:
example.com.    MX    10 mail.example.com.
mail.example.com.    CNAME    example.com.
example.com.    A    123.123.123.123

Besides this MX example, using CNAMEs is a good thing, it makes
management of the records much simpler.
For simple/small domains I usually just assign the root of the domain
an A record, and CNAME everything else to it.
@    A    123.123.123.123
   MX    10 @
www    CNAME    @
mail    CNAME    @


For more complex domains use A records for actual server names, and
create CNAMEs for each service on the server.
server1    A    123.123.123.123
server2    A    234.234.234.234
mail    CNAME    server1
www    CNAME    server2
secure    CNAME    server2
db    CNAME    server1
...

This strategy makes moving services among servers very simple, and
changing an IP of a server very simple as well.