i'm currently running exchange 2010 and i recently acquired a new domain name because i'd like to be able to accept emails using the new domain name. all the dns stuff is set up and i've added the domain to the list of accepted domains in hub transport. however, when i go to create new email addresses, the new domain name is not in the drop down list of logon domains. how do i get it there?
As Shane has mentioned, it's a bit different. I do think it's generally a good idea to have UPNs match up to email addresses though as it makes users' lives easier (I fight for the users). So if you'd like to do that, add it as a UPN suffix for the forrest. There is a Microsoft KB article available here:
Here's a basic recap of the KB article:
Once that's done, you may add user accounts with the UPN suffix you desire.
You're creating a user, not an email address. A logon domain is an Active Directory domain, which doesn't necessarily correlate in any way with a user's email address or Exchange's authoritative domains list.
Create the account in the domain that makes sense, then get the user a primary SMTP address and recipient policy that fit with the account's needs.