[Dovecot] Restricting IP and/or user access (POP3/IMAP)

[Jos Chrispijn]

Phil,

> The documentation says to authenticate only from a specific IP or network…
> if you set this to 127.0.0.1 to indicate the local loop then this
> effectively blocks every IP address but this one. Since the extra field is
> in passdb then this would imply it can be done on a per user basis
I considered this solution, but it isn't what I have in mind; everyone 
must be able to fetch POP3/IMAP mail, but some users have to be blocked.
In other words: user JohnDoe can't fetch his mail thru Dovecot, but can 
still logon thru webmail with his username/password. JaneDoe can both 
fetch her mail with POP3/IMAP as well as thru webmail with her 
username/password.

I think I overlook something here, but haven't find a right solution 
yet. Perhaps a plugin??

Jos