Migrating from Exchange
This is a step by step guide to migrating your domain's email from Exchange to Zimbra. It will take some side trips along the way -- my example domain, for instance, has Exchange 5.5, and yours will probably be newer, and is behind an older MailScanner box, which you might not be -- but hopefully the 5000 foot view information will be of help to you, and you can figure out the 500 foot stuff yourself when it differs.
This is a work in progress, as long as this notice remains, and that's why it's not yet linked from anywhere, including categories. Once I'm done with it, I'll link it in. (And my apologies it's taking so long; work and my personal life have both swamped me this
monthyear. I've just (mostly) completed building 3 new facilities for my company, and I should finally have time to finish both writing about this, and doing it. --Baylink)
My goal in migrating to Zimbra was never to leave myself in a position where an executive mandated a back-out, and I had to lose something to do it.
Accomplishing this wasn't too overly difficult, but did require some forethought, and I'll try to put that all down here, so you don't have to do it over again.
The Old Installation
The email 'solution' from which we were trying to extricate ourselves was a Win2k machine running Exchange 5.5, authenticating to a PDC running NT4. Yes, NT4.
Now that you're done laughing...
I do have a reasonably recent Samba installation in the building, also authenticating off that PDC, but I didn't want to migrate domain control in the middle of the rest of the mess, if I didn't have to.
If I have to set some passwords by hand, that will be acceptable to me for now.
Part of the reason for this migration is that my 16GB-limit mailstore was at about 15GB. I think. There's a bug that keeps me from getting accurate answers to that question, that I apparently can't upgrade around, either.
As you might expect, I had to grow some grass to get a hamburger for lunch (the cattle need to eat, you see); let's look at what that entailed.
Build a Machine
Based on the fact that RHEL5 is a supported platform, and that CentOS5 is supposedly bug-for-bug identical to it, that's what I chose for my pilot install. There's a move on to make CentOS a formally supported platform, but since an RHEL license costs as much a year as the Zimbra license does, for my mailbox count, I figured it couldn't get me in any trouble I couldn't get myself out of. So far, that's proven true.
So I built CentOS5 with KDE, and upgraded it to current.
Then I downloaded Zimbra for RHEL5, and built it. (We've since upgraded to 5.0.18)
Stage 1: The Zimbra Server
Stage 2: On-line testing
DNS set up