[lug] User Account Migration

[Sean Reifschneider]

On Mon, Jul 09, 2001 at 09:48:08AM -0700, Stephen Smith wrote:
>The server has approx. 600 user accounts doing
>POP mail only.

I don't know of a migration HOWTO.  However, if I were doing such a thing
I'd be using QMail as the MTA, with vpopmail handling the user accounts.
Vpopmail allows you to have a web-based administration of users on a
per-domain basis (if you're hosting more than one domain), and deals with
virtual users.  That way, the users don't have to exist as system users.
That reduces some amount of exposure to compromise.

Other tools to consider are CourierIMAP if you want IMAP, relay-ctrl which
gives POP-authenticated SMTP relaying, and sqwebmail is a fairly good and
easy to set up web-based e-mail program.

One of the tricks you could do is to set up a POP proxy server so that you
can migrate POP users one-by-one.  Users that had been migrated would get
their mail from the redhat box, users that hadn't would be proxied back to
the other box.  I don't know if there's an existing tool that will do
exactly that, but it should be pretty easy to set up if not.

The migration process tends to be fairly automatable, but usually requires
writing some scripts that are specific to your setup.

The basic migration strategy is:

   Shut down both mail servers.
   Copy the accounts from old machine to new.
   Copy the mail from old machine to new.
   Test new machine.
   Configure old machine to act as secondary MX for new machine.
   Test old machine.
   Modify DNS so new machine is primary MX.
   Re-start both mail servers.
   Watch logs for whatever you've missed.
   Test again from outside world.

Sean
-- 
 The early bird may get the worm, but the second mouse gets the cheese.
Sean Reifschneider, Inimitably Superfluous <jafo at tummy.com>
tummy.com - Linux Consulting since 1995. Qmail, KRUD, Firewalls, Python