Email Setup

first are you running exchange 2000 or 5.5
a good start for exchange 2000 would be dual PIII at least 500mzh and 512mb ram you should mirror the system drive and raid 5 the information store. if you limit your users to about 200mb x 500 users x 2 for space growth your information store drive needs to be at least 200gb or smaller if you change the limit.

do you need help determining hardware requirements, access methods, or what?

Machine requirements for 500 users:
dual processor, 512MB-1GB, 15-20 GB raid 5 disk space + 15-20GB for recovery and maintenance. depending on mail traffic you can easily generate that size PRIV.EDB in a few months, to perform offline maintenance you need as much disk space free as you PRIV.EDB is. RAID 5 the EDB files, place the edb.log files on a Mirrored set, ensure circular logging is not enabled, you will easily go through 100 logs a day. Get your self a DLT drive to do the backups.

Are people going to be accessing their email external to the company network?

OWA, POP3, IMAP4 are reasonable alternatives to full outlook access. But you will want to secure them using SSL, so that all communication between server and clients is encrypted. If people are going to dial into the corporate network, full outlook access is advisable along with offline folders.

Let me know if you need anymore information.

I can tell you that I support about 800 users on a Proliant5500 (dual CPU - PII/450 with 1gig of RAM) and we have not seen performance limitations (typical CPU utilization seldom higher than 20-25%). So the recommendation above is plenty from a workflow perspective. Keep in mind that Exchange really puts your RAM to work so I would consider 1-2gig rather than the 512 suggested above.

As far as drive space, I personally think 200meg per user is WAY too much to allow and a 100gig InformationStore is WAY too big to manage on one server. If you ever have to run database diagnostics or a recovery procedure, you'll need two full days. But also keep in mind that not all users are space hogs - our limit is 150meg but we only have about 20 users (out of 800) that actually bump the limit. Our total Information Store is now about 17gig on that server and when it hits 20gig, I'll start migrating users to another server.

Keep in mind also that for some of the repair processes you need free space equal to the total size of the databases (priv.edb, pub.edb, dir.edb) plus 10%.

So... lotsa RAM, lotsa drive space, CPU is relatively less important.

paul