[Dovecot] pop3_lock_session question

[Seth Mattinen]

Justin Krejci wrote:
>>> Could it be some (older?) webmail clients that use pop3 instead of imap?
>> I wouldn't expect a webmail client to hold a pop3 connection open
>> across multiple web requests.  We have standard webmail clients
>> available for customer use, but they use IMAP.  With the frequency
>> we're seeing this problem, I'd expect it's more likely to be something
>> newer or more commonly used.
> 
> Presuming you've been able to identify which users this is affecting I would
> suspect you could go back to those users and determine what clients they are
> connecting with and then interested parties (dovecot devs?) could perform
> further investigation in a lab or whatever to determine what is going on.
> Maybe the client(s) is/are just whacky or there is a bug somewhere.
> 
> You can also track down the source IP addresses which may give you an idea
> as to the client as well. If it is a RIM subnet then you may be able to
> assume it's a blackberry. If the PTR record for the IP is
> webmail.somecompany.com then you can probably contact the company and
> discuss with them. Etc. Some companies may have a proxy or something that is
> attempting to hold the connections open for faster response times maybe
> geared for slow link connections. People do a lot of "interesting" things
> from time to time.
> 

Like imapproxy which holds the connection for subsequent requests to
avoid the short-lived HTTP connection issue. I certainly recommend it
for squirrelmail installations since squirrelmail can't IDLE the connection.

~Seth