Just to put poor Jenny's mind at rest.
Far be it for me to openly defend a MS product but Laurie you are a bit of the mark with some of your comments :o)
Exchange is fully proprietary, and doesn't run IMAP.
2000 does and 5.5 could be made to with some persuasion.
You're restricted to Outlook as a client.
But only if you want all of the Exchange functionality and even then as Adam and others have pointed out it is possible to use other clients (or even the Web access thing on it's own, mind you good luck if you want it to play nicely on anything other than IE)
Note too that it's impossible to restore individual emails if lost
Not true, it is difficult to restore individual mail boxes and was even more so on 5.5. But if you have the right backup solution or a clever admin it is not impossible.
guaranteed data loss if the internal DB dies (which it is prone to do).
5 and 5.5 were especially was known to damage their Information stores if they crashed in some instances, but even then it was possible to run repairs to the DB and get it back. To say that Exchange is prone to doing this is a bit of an exaggeration. I think I have encountered it about 2-3 times on 5 or 5.5 and never on 2000. Honestly if you have an Exchange server that is doing that regularly then I would suggest that there is something wrong with it.
To overcome this, big corporate users run two instances of Exchange, and > > restore to the "dummy" one whence individual emails can be copied out, and the "live" one left alone.
I think you may be confusing a few things here, One is a repair technique that can be used if you only have Mickey mouse backup software (like the rubbish that MS provide) and need to restore an individual mail box, another is a repair technique that can be used if half the DB is shot (ie the Public store is dead but the private one is ok) but the main reason you will see more than one Exchange server is that due to the innefficiencies of Exchange it does really need to be multi homed once you start to scale up the number of users
Exchange uses an internal DB to store email (as opposed to IMAP/POP) because NTFS isn't good enough at securing private emails, so the DB adds an extra layer of permissions, ACLs etc.ers.
Exchange uses a DB because frankly it's the right thing to do given what Exchange does. To prove this point go to a site that has say 200 user mailboxes and send an all staff mail with a 1MB attachment. Notice how quickly that message got to all users ? See how the Information store didn't grow by 200MB ? That's why Exchange uses a DB it has nothing to do with permissions.
Frankly, a mysql-driven postfix system using SASL and courier with any client you like is way better, and a helluva lot cheaper...
True but can it provide everything (from an end user perspective) that Exchange/Outlook can, to my mind this is one of the big gaps in any potential Linux Migration. I've tried several things but I have never been able to provide every feature without resorting to several client applications. After working with Outlook for so long end users are quite settled into having everything in one place.
I'm sorry Laurie, I don't mean to attack your post here. But to my mind Exchange/Outlook is possibly the best thing MS ever came up with and it's the one thing that there isn't any Plug in and go Linux equivalent of. I'm not saying it's without it's flaws and I've spent many a cold night banging my head against a dead exchange server, but for many people it works very well and for the most part it is reasonably reliable.
SuSE Openexchange is getting there, but not quite.