We have a client running 2008 SBS on an old HP Server which is rather underpowered. The current domain has about 22 users with Exchange mailboxes.
Traditionally when I replace a server like this I tend to prefer to start again with a who,e new domain so that we have a clean slate approach and have always avoided the migration route. What I usually do is export each clients email to a pst file, copy that and the profile folder into a new profile in the new 2011 domain then import the email into the new Exchange via Outlook.
On a couple of occasions though I have experienced a problem which caused issues when users tried to reply to old emails sent from an user on the old domain (they get the bounce back referencing FYDIBOHF23SPDLT. I never really found a simple or effective cure for that issue (was told to manually add x500 address for each user) and ended up just telling users to start new messages to colleagues rather than replying to old ones.
What I would like advice on is how can I avoid this problem occurring this time round without having to manually add x500 addresses for 22 users?