[KLUG Members] Smart Mail Router

[Jeremy Leonard]

I'm in the process of migrating 600 users from one mail system to another.

I need a what to route incoming Internet email to the correct system.

Is it possible to set this up using a Linux box. If so, what would be 
the best way to do this?

Example:

John is on the old system.
I need email sent to john at oldserver.
Once I move John to the new system I need email sent to John at newserver.

I only have one domain name and do not want to get another or change the 
existing one.

Something automatic would be extremely awesome but I'd work with edit 
two lists of users manually.

Thanks,
Jeremy