CNAME for main domain

[Danny Mayer]

At 07:41 AM 11/27/02, Gregory J. wrote:
>Am I correct in understanding that a PTR record can indicate a CNAME?

I don't believe that there's anything wrong with that and there's nothing I
could find in the RFC's to indicate otherwise. Mark will correct me if
I'm wrong.

>For some reason I thought that this would interfere with certain
>programs (like MTAs and SSHD) that do reverse DNS calls: I thought
>that in trying to verify a hostname they would look it up, follow any
>CNAMEs, note the A record's name, and verify that the IP's reverse
>mapping matched the A record. Would they instead check that the IP
>matched either the A record or one of any CNAMEs?

That depends on the application.  You need to ask the groups responsible
for those applications on how they check them.

>  If a PTR at a CNAME
>is both without the complications I described and standards-legal,
>then it would indeed prevent the reverse-record untidiness I feared.
>(It struck me as tacky and artificial to have an IP resolve to the
>zone apex.)
>
>- Greg

Danny