Multiple mail domains or multiple windows domains or both?

Either way, there are some docs that should be helpful at
http://www.microsoft.com/exchange/library

You can deploy a single server for this.  A FE/BE scenario is nice if you
want to scale the solution for more users, but it's not a requirement.  The
extra VS's would be more for the UPN logon than a requirement as well.  You
can have them login with domain\username credentials and not make
modifications to the VS's.  You will however need to domainprep each domain
they live in (if windows domains you're talking about) and create a rus for
each.  If they all have the same authentication domain, then it's recipient
policies you're after.

It would be nice if Microsoft would make the UPN logon easier to work with
and deploy than to have to fiddle with VS's though.

Al

Each account will be stamped with a primary SMTP address.  You can add different SMTP addresses to these accounts, as long as everyone has the similar SMTP address, they can log in with their domain\user account.  Hope that helps.

 Hello to all Ng,

 We are in need to deploy Exchange 2003 in our organization our management
 want us to implement just one back end Exchange server, matter of costs they
 say...

 Anyway, we need to implemente Exchange to support a few different domains so
 we'll create needed SMTP VS but I was wondering. With just one back end
 server users from different domain will=B2 be able to log gon to OWA using
 username@mydomain.com? I need a FE/BE to accomplish this? If they can't logon
 using UPN can they logon using mydomain\user?

 Any answer or if someone can point me to a good article I'll apreciate very
 very much.

 Thanks in advance, Daniele