John R Pierce wrote:
> Les Mikesell wrote:
>> Mail isn't supposed to be rejected for this, but some places probably
>> do. A more correct approach is to have one name with the A record and
>> the matching ptr and make all of the other names CNAMEs.
>>
>
>
> no, no, no! CNAMES are discouraged as they create additional work
> for everyone else's DNS servers.
Is there an RFC to that effect? I didn't realize DNS lookups were a
scarce resource.
> the only time its proper to use a
> CNAME is when you are referencing a host on someone else's network who's
> addressing and management is beyond your control and you won't get
> notifications if its changing.
I suppose something like this is overkill, though...
Non-authoritative answer:
www.redhat.com canonical name = www.redhat.com.edgekey.net.
www.redhat.com.edgekey.net canonical name =
www.redhat.com.edgekey.net.globalredir.akadns.net.
www.redhat.com.edgekey.net.globalredir.akadns.net canonical name =
e86.b.akamaiedge.net.
Name: e86.b.akamaiedge.net
Address: 64.215.167.112
> for email, all the various domains should have MX records with the mail
> server's "true" name.
MX records don't have much to do with the system sending mail.
--
Les Mikesell
lesmikesell at gmail.com