imap

nginx: high performance smpt/pop/imap proxy

nginx is a high performance smtp/pop/imap proxy that lets you do custom authorization and lookups and is very scalable. (just add nodes) Nginx by default is a reverse proxy and this is what it is doing here for pop/imap connections. It is also an excellelent reverse proxy

General Discussion

Scaling IMAP and POP3

Just thought I'd drop a brief suggestion to anyone building a large mail system. Our solution for scaling mail pickup was to develop a sharded architecture whereby accounts are spread across a cluster of servers, each with imap/pop3 capability. Then we use a cluster of reverse proxies