Am 11.04.2014 17:49, schrieb morrison:

Dovecot Wiki states that mail process (IMAP/POP3) is able to handle multiple client connections as the same time to save CPU and memory resources (client_limit > 1). Although this approach is not recommended due to latency and probably security issues, it does help increase the overall capacity of a mail server. Is it possible (or planned) to add a feature such that mail client connections of the same user from a same IP are directed to a same mail process? In most cases, such connections come from a same mail client (e.g. in Thunderbird, each mailbox is a connection). The end user (human being) can work on one mailbox at a time, the latency will be non-obvious. And since all data being processed belong to the same user, security is a non-issue.

http://wiki2.dovecot.org/LoginProcess

"High-performance mode" is already there and no, forget the broken idea "but only the same user / ip" because you have no clue if it is a different user coming from the same IP until the connection does auth

• if it does auth and it was not the same you are fucked
• you can't handle the connection to a different process
• even if you can - your login data are already sent

"In most cases, such connections come from a same mail client" that made sense 10 or 15 years ago, these days *most cases* are mobile clients coming through carrier-grade NAT, networks behind a NAT or public access points shared by all sort of users

so no - you have only two choices

• performance
• security

any other conclusion base don a client IP is broken