[cobalt-users] MX records and off-server mail servers

["Rick Ewart" <cobalt@xxxxxxxxx>]

Hello all.

I have seen several threads about this issue, but none that offered a clear
answer complete instructions, so I figured I would summarize for anyone who
is still having problems... Perhaps an addition to the "how to" book....
Please correct any errors.

Problem - Client has own mail server on his network but you are hosting his
website and possibly providing other services for him. How to setup domain
and DNS to properly serve him.

Assumptions - client's mail server is at 222.222.222.222, your server is at
111.111.111.111. Domain is domain.com, and I think also that you are on a
Raq3 or 4 (don't know much about the other systems)

Solution.

Setup domain, and do not specify any mail server aliases in the site
settings. Also, don't setup any aliases under the usernames on the site.
Then, go to the email parameters of the mail server, under the entire
server's control panel. Check to make sure that the "Host/Domain Aliases"
doesn't contain domain.com or www.domain.com. Save changes if any.

Go to DNS and setup the following:
A record - domain.com to 111.111.111.111
A record - www.domain.com to 111.111.111.111
A record - mail.domain.com to 222.222.222.222
MX record - domain.com to mail.domain.com
MX record - www.domain.com to mail.domain.com
Save changes

That should do it. It addresses 2 problems - mail getting sent on to the
client's server when it originates outside, when addressed to
user@xxxxxxxxxx and user@xxxxxxxxxxxxxx [gotta wonder if anybody does that
though]. It also addresses the problem of mail originating from the server,
such as form submissions and/or mail from other clients hosted on the same
server. This was the kicker, which the server control panel's email server
settings was wreaking havoc. With the domain name listed in the "host/domain
aliases", the server has a tendency to keep the mail on the server [or
rejecting with "no such user"] instead of forwarding to the client's offsite
mail server.

Well, I hope that helps someone. Thanks to Filiberto Ricci for helping
someone else with the problem - found the missing piece in the archives and
figured it out.

Rick Ewart