Say you want messages addressed to 'user1' to be redirected to 'user2' if they came from email@example.com
This is an unusual requirement, so there is no way to do it in VPOP3.
To do this, create a download rule as:
Note that this will cause the matching messages to be ONLY sent to user2. If the message was originally sent to user1 & user3, the rule will make it ONLY go to user2. There is no simple way to make the message go to user2 and user3. This would be possible using the Lua 'User Routing' script facility but that is outside the scope of this article.
If you want ALL messages from firstname.lastname@example.org to be redirected to 'user2', you could use a “From” Mapping