We are now running a mixed Exchange environment.We originally had 2 Exchange 2003 servers in a FE/BE configuration. We have since installed a single Exchange 2007 server containing the mailbox, client access and hub server roles.A decision needs to be made about the need for an edge server when the 2003 boxes are decommisioned. We do not have a large number of mailboxes. The only reason we had a FE/BE architecture was because of the Microsoft best practice where virus and spam scanners should be separated from the machine where mailbox databases are stored due to risk of data corruption.Now that Exchange 2007 uses the new Forefront system, is it still recommended to an edge server or could we run everything from one box? As I mentioned before we do not have a large user base - probably around 30-40 mailboxes.