[Dovecot] Maximum number of connections from user+IP exceeded

[Frerich Raabe]

On 2013-08-19 23:00, Stan Hoeppner wrote:
>> * a IMAP client opens one connection *per folder*
>
> What do you mean by "per folder"?  I've been limiting Tbird to 2 IMAP
> connections for many years and, unsurprisingly, it never opens more 
> than
> two IMAP connections to Dovecot no matter how many folders I access,
> tabs I have open, or searches I perform, etc:
>
> tcp 0 0 192.168.100.9:143 192.168.100.53:1663 ESTABLISHED 13189/imap
> tcp 0 0 192.168.100.9:143 192.168.100.53:1672 ESTABLISHED 13192/imap
>
> And with the default TB limit of 5 it never opens more than 5.  Which
> clients exhibit this "per folder" connection behavior?  That seems
> totally unnecessary.

Any client which supports the 'IDLE' command does this; it's a 
mechanism
to avoid that a client has to poll the IMAP server for new mail. The 
client
does an 'IDLE' call *per folder* which only returns when the server 
adds
new mail to the folder. Hence, the IDLE call blocks the connection, 
which
is why mail clients which use IDLE have to establish multiple IMAP
connections, one per folder which is monitored using this feature.

-- 
Frerich Raabe - raabe at froglogic.com
www.froglogic.com - Multi-Platform GUI Testing