CNAME for main domain

[Kevin Darcy]

"Gregory J." wrote:

> Is it valid to have the "main" (I call it that for inability to think
> of a better word) domain in a zone a CNAME? This zone file for
> example:
>
> $TTL 86400
> @       IN      SOA     ns1.domain.com. admin.domain.com. (
>                         2002112301      ; Serial, YYYYMMDDXX
>                         3600            ; Refresh, 1 hour
>                         1200            ; Retry, 20 minutes
>                         2592000         ; Expire, 1 month
>                         600 )           ; Minimum, 10 minutes
>         IN      NS      ns1.domain.com.
>         IN      NS      ns2.domain.com.
>         IN      CNAME   host1
> host1   IN      A       123.456.789.101
>         IN      MX 10   host1
>         IN      MX 20   host2
> host2   IN      A       123.456.789.102
>         IN      MX 10   host2
>         IN      MX 20   host1
>
> Is the CNAME record correct? I set it up so that http://domain.com/
> points to host1, which serves the organization's Web site. I could
> have made it "IN A 123.456.789.101," but I didn't want to have two
> mappings to the same IP -- it's untidy for reverse DNS.

No, when a name owns a CNAME, it cannot legally any other record. The
zone apex in your example owns an SOA and 2 NS records, so it cannot
legally own a CNAME record.

If you want the zone apex name to resolve to an address, you must use an
A record for it rather than a CNAME. There's no problem making the
"www" name an alias for the zone apex name, however, so that should fix
your reverse-record "untidiness".


- Kevin