Re: [cobalt-users] MX record question / Raq4i

[Jeff Lasman <jblists@xxxxxxxxxxxxx>]

Bruce Timberlake wrote:

> The only other thing you need to do is have DNS "A" records defined for
> each of those other aliases (domain.com, mail.domain.com, etc) which
> point to the IP address for host.domain.com.

...<stuff snipped>...

> You would only set up multiple MX records for a domain if you have
> backup mail servers that could accept mail for your domain if the main
> mail server can't (offline, etc).

While your second statement IS true, your first isn't.  Because the
Internet sees "domain.com" as a completely different domain than
mail.domain.com, each is a "domain" and each needs a primary MX record.

Because many smtp servers will default to using an A record if there's
NO MX record for a domain doesn't mean all will, and doesn't mean you
shouldn't have those MX records.  Each of these MX records will be seen
as completely independent.

So yes, you should have the following MX records:

 domain.com.      IN      MX      30      domain.com.
 mail.domain.com. IN      MX      30      domain.com.
 www.domain.com   IN      MX      30      domain.com.

And while I hate to disagree with someone from Sun/Cobalt, the fact is
that yes, Bruce, I have written the book on DNS (just haven't gotten it
published yet, but I'm working on it <smile>).

Jeff
-- 
Jeff Lasman <jblists@xxxxxxxxxxxxx>
Linux and Cobalt/Sun/RaQ Consulting
nobaloney.net
P. O. Box 52672, Riverside, CA  92517
voice: (909) 778-9980  *  fax: (702) 548-9484