Mailing List SIMS@mail.stalker.com Message #15425
From: Christopher Bort <cbort@globalhomes.com>
Subject: Re: SIMS dual domains
Date: Wed, 7 Feb 2007 09:45:32 -0800
To: SIMS Discussions <SIMS@mail.stalker.com>
X-Mailer: Mailsmith 2.1.5 (Blindsider)
On 02/07/07 at 06:28, Todd Reed wrote:

> Hi all,
>
> Still running SIMS here despite all rumors to the contrary.
>
> I need to run dual domains on SIMS as the organization is moving to a
> new domain name. We want mail sent to user@olddomain.com or
> user@newdomain.com to both go to the same user mailbox.
>
> My checklist is as follows:
>
> Turn down TTL's on existing domain.

Why? If you follow your plan outlined below, the existing MX,
mail.olddomain.com, will continue to point to your mail server without
interruption, no? Whether a sending MTA uses a the old A record from a
cache or gets the new CNAME, it will still resolve to the IP address of
your SIMS machine. Unless you're changing the IP address of your server,
but it doesn't sound like that's the case.

> Establish new domain with A, and MX records pointing to SIMS.
>
> Give SIMS it's new domain name: mail.newdomain.com
> Set up a routing entry: *@olddomain.com=newdomain.com

That should be:

<*@olddomain.com> = *@newdomain.com

However, if all user names are the same for both domains, you can simplify
that to:

olddomain.com = newdomain.com

Put this at the top of your router, above any entries that route individual
addresses within the domains.

> Set up CNAME on old domain name record:
> mail.olddomain.com CNAME mail.newdomain.com
> Remove A record for mail.olddomain.com
> MX record on old domain points to mail.newdomain.com

That's all optional and entirely up to you. The record for
mail.olddomain.com can remain as an A, especially if you're reasonably
confident that your server will keep the same IP address for a while.
CNAMEs can get messy, so I usually try to avoid them when an A record will
do the job.

More to the point would be to simply change the MX record for olddomain.com
to point to mail.newdomain.com (an MX does not have to be in the same
domain):

olddomain.com   MX   10   mail.newdomain.com

Again, you don't need to fiddle with TTLs here because mail.olddomain.com
and mail.newdomain.com will point to the same IP address. If you make
mail.newdomain.com the MX for olddomain.com, then you can remove the
A|CNAME for mail.olddomain.com entirely after its TTL expires.

> Then sit back and watch the mail get delivered.
>
> I don't recall the best way to set up the router entry as it's been
> awhile since I tried this. Any tips on this checklist or the correct
> router syntax appreciated.

--
Christopher Bort
Homes Magazine
email: <cbort@homesmagazine.com>
website: <http://www.homesmagazine.com/>
FAX: 775-284-1298
Phone: 775-284-1294

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