Quoting "Daniel L. Miller" <dmiller@amfes.com>:
On 6/24/2010 4:23 AM, Timo Sirainen wrote:
I'd recommend also installing and configuring imapproxy - it can
be beneficial with squirrelmail.Do you have any about a real world numbers about installation with
and without imapproxy?What, you want me to actually back up that statement with data?!
Who do you think I am?! Never mind - don't answer that.
I don't have any numbers either, but...
I know when I was playing web clients - particularly squirrelmail -
there was a definite perceived improvement - but I never measured it.
Webmail clients are basically stateless. Over time, they have "cached" some info for performance, but basically they are still stateless. So almost any time you click on a link dealing with an email (delete, purge, next message, forward, etc) it has to open a _new_ connection to the imap (or pop) server, which means a new login.
Simple proxies (like say perdition) don't help, as each connection will still be a new login.
Some proxies (like imapproxy) however can keep a login session open, with the proxy caching the authentication issue. For each connection after the first, it can do the authentication itself and use the existing login connection to the pop/imap server, avoiding a login for each operation after the first (until a timeout is reached). By avoiding the constant login/logout cycle, it will generally perform at least slightly better with the proxy than without (no new connection overhead, no login and logout overhead, same over head most everywhere else unless the proxy's authentication is slow).
That's why a connection/authentication caching proxy is generally recommended for webmail setups. It also keeps the log files from filling up on the pop/imap server with the constant login/logout log lines.
This is also why you can get a speedup even if the proxy is on the same host as the pop/imap server (assume sufficient memory and other resources).
Daniel
-- Eric Rostetter The Department of Physics The University of Texas at Austin
Go Longhorns!