Postfix Mail Server Migration

Corey Edwards tensai at
Fri May 9 17:14:03 MDT 2008

On Fri, 2008-05-09 at 17:05 -0600, Dallin Jones wrote:
> I am looking at migrating my Postfix Mail server from one machine to
> another. I have it all set up and working and I am ready to flip the
> switch. One thing that I have noticed in my testing is that once I
> change the IP address to the new address, the mail client doesn't
> fetch any mail from the new server unless I delete the account and
> create it again.

Which mail client? That's where I suspect the problem is. Many,
especially Windows ones, will not re-resolve DNS names until the
computer is restarted.

> Also, since the server is setup with IMAP, to copy all the messages
> from machine A to machine B, should I use rsync, or is there something
> else that should be used?

In your case, you're probably best of using rsync. There are some other
tools such as imapsync which can do individual imap boxes, but when
you're copying all the mail from two identical platforms rsync will be
faster. One hint, start rsync beforehand so that when you run the final
sync, you only have to push the last few diffs. Use that --delete
option. When mail volumes are big enough and networks are slow enough,
rsync makes life livable. I once moved 250GB of mail over a 20mbps link,
one account at a time. It only took 2 weeks but it was pretty seamless
for the users.


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