Re: moving mail system from one ISP to another

[Michael Wood <mwood@its.uct.ac.za>]

On Tue, Jan 15, 2002 at 12:24:26PM +0100, alexis bory wrote:
> Hello,
> 
> I have to control the transfert of the mailboxes
> of one of my customers from his old ISP to his
> Mother-Company-Centralized-Corporate-Lotus-Notes.
> 
> I wonder if abruptly changing the MX for his domaine
> wouldn't cause any trouble. Is it possible to configure
> a forward in the old MTA before changing the MX ? I
> mean this to avoid trouble during the time all the DNS
> get the rigth record.

You can, as others have mentioned, get your MTA to route the
mail to the new server explicitly.

The other option is to change the DNS and then tell the old MTA
not to treat the domain as "local," but to continue to relay for
the domain.  Just make sure that the old MTA knows about the DNS
updates before doing that.

Then what will happen is that the old MTA will receive mail for
the domain from people who haven't yet seen the DNS update, and
it will route it to the destination mail server by looking up MX
records etc., as usual.

The only problem with this approach is that there's a small gap
between changing the DNS and changing the MTA config during
which some mail might be delivered to the old MTA, but not
forwarded to the new one.  This may or may not be a problem in
your case.

-- 
Michael Wood <mwood@its.uct.ac.za>