[Dovecot] Prevent Download messages from server

[Peter Mogensen]

 > we have no problem, just i want to learn how can i do that. i think
 > it's clear .

Well... I'm pretty sure most others don't.

But anyway. As in ALL Internet protocols (IMAP being no exception), 
letting the client read data on the server requires it to download the data.
Preventing download will prevent reading the mail. Period.

So if you're fine with that and just want to learn how to do it, then 
just disable the account in the user database.

/Peter