I’ve been busy the past few weeks consolidating servers. We have some really old servers from one of our VPS providers that really needed to be decommissioned. The problem with a project like this is that the older they are, the more stuff is built into it – crons, url rewrites, custom DNS, the list goes on. And since these are working sites, we could not afford downtime and each migration needed a few undisturbed hours.

One of the major task was to migrate email accounts from our legacy VPS running FreeBSD 4.7 to newer ones running 6.3. Here’s how I did it.

1. Copied the passwords from /etc/passwd in the older 4.7 servers.
   (Copy the part right after the name until right before the colon – e.g. mike:54YBKHNIE0.3L: ) UPDATE: Someone suggested a utility called ‘vipw’. Haven’t tried it yet.
2. Pasted them into /etc/master.passwd of new server.
   (Create the users you need first with any temp password. The paste the one above between the name and colon)
3. Ran pwd_mkdb -p /etc/master.passwd
4. Updated the MX and A record for the mail server to point to the new server. We normally migrate email and web separately to minimise downtime. Using a good DNS service like DNS Made Easy allows you to set a low TTL for these changes to take affect quickly.
5. Finally, I commented out the hostname in /etc/hosts on the old server to tell it that it no longer manages emails for this domain.
6. Finally finally, I forwarded old emails using Mutt to the new account.

Hope this helps, worked wonders for us. Clients had no disruption to their emails which meant little grief for me!