multiple IMAP sessions when connecting from one client
Hello,
I am using Postfix/Dovecot/IMAP.
Everything is working fine, but I have noticed that every time I connect with Thunderbird to my server via IMAP, not one but 4 connections are being logged into /var/log/mail/mail.log:
2014-08-27 09:17:46 dovecot: imap-login: Login: user=<martin>,
method=PLAIN, rip=11.22.33.44, lip=55.66.77.88, mpid=12519, TLS,
session=
This looks like 4 separate sessions are created when I log in from one client.
Is this normal behavior? Can somebody please explain why this is so?
My Dovecot version is 2.1.7
regards, Martin
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On Wed, 27 Aug 2014, Martin Vegter wrote:
This looks like 4 separate sessions are created when I log in from one client.
Is this normal behavior? Can somebody please explain why this is so?
because Thunderbird wants to access 4 mailboxes simultaneously, e.g. to check or wait for new messages.
Steffen Kaiser -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux)
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On 08/27/2014 11:22 AM, Steffen Kaiser wrote: On Wed, 27 Aug 2014, Martin Vegter wrote:
This looks like 4 separate sessions are created when I log in from one client.
Is this normal behavior? Can somebody please explain why this is so?
because Thunderbird wants to access 4 mailboxes simultaneously, e.g. to check or wait for new messages.
That would make sense.
But I have 5 mailboxes in total (Inbox, Sent, Draft, Archive, Trash). Although, I suspect Inbox has special status because it is not defined together with the other four in 15-mailboxes.conf
Zitat von Martin Vegter martin.vegter@aol.com:
On 08/27/2014 11:22 AM, Steffen Kaiser wrote: On Wed, 27 Aug 2014, Martin Vegter wrote:
This looks like 4 separate sessions are created when I log in from one client.
Is this normal behavior? Can somebody please explain why this is so?
because Thunderbird wants to access 4 mailboxes simultaneously, e.g. to check or wait for new messages.
That would make sense.
But I have 5 mailboxes in total (Inbox, Sent, Draft, Archive, Trash). Although, I suspect Inbox has special status because it is not defined together with the other four in 15-mailboxes.conf
This is a client setting, so you have to ask the Thunderbird
developers why they open that number of connections. Most of the time
it is done to not block the UI on longer IMAP operations.
Regards
Andreas
On 8/27/2014 7:31 AM, lst_hoe02@kwsoft.de wrote:
Zitat von Martin Vegter martin.vegter@aol.com:
On 08/27/2014 11:22 AM, Steffen Kaiser wrote: On Wed, 27 Aug 2014, Martin Vegter wrote:
This looks like 4 separate sessions are created when I log in from one client.
Is this normal behavior? Can somebody please explain why this is so?
because Thunderbird wants to access 4 mailboxes simultaneously, e.g. to check or wait for new messages.
That would make sense.
But I have 5 mailboxes in total (Inbox, Sent, Draft, Archive, Trash). Although, I suspect Inbox has special status because it is not defined together with the other four in 15-mailboxes.conf
This is a client setting, so you have to ask the Thunderbird developers why they open that number of connections. Most of the time it is done to not block the UI on longer IMAP operations.
BTW this is configurable in Thunderbird:
Tools->Account Settings->Server Settings->Advanced->Maximum number of server connections to cache
Default is 5 IIRC. I find the Tbird UI is much more responsive if set to 1, for "normal" IMAP use.
On -10.01.-28163 20:59, Martin Vegter wrote:
I have noticed that every time I connect with Thunderbird to my server via IMAP, not one but 4 connections are being logged [...] Is this normal behavior?
From the point of view of dovecot, as a *server* implementation, it is pretty normal to answer as many IMAP connections as a legitimate client sees fit to start. After all, the IMAP protocol is *designed* to allow multiple concurrent connections for the same user/mailbox even from *different* clients (and NATed clients exist).
Note, however, that dovecot has various limits set and active by default, the most relevant for this matter probably being a mail_max_userip_connections of 10.
From the client's perspective, there may be good reasons to have several connections at once (in particular, ability to run several operations in parallel), and then there obviously are less convincing ones as well (I've seen appliances checking for new mail every couple minutes, connecting for less than 1s, but opening *TWO* connections to do so).
Regards, J. Bern
*NEU* - NEC IT-Infrastruktur-Produkte im http://www.linworks-shop.de/: Server--Storage--Virtualisierung--Management SW--Passion for Performance Jochen Bern, Systemingenieur --- LINworks GmbH http://www.LINworks.de/ Postfach 100121, 64201 Darmstadt | Robert-Koch-Str. 9, 64331 Weiterstadt PGP (1024D/4096g) FP = D18B 41B1 16C0 11BA 7F8C DCF7 E1D5 FAF4 444E 1C27 Tel. +49 6151 9067-231, Zentr. -0, Fax -299 - Amtsg. Darmstadt HRB 85202 Unternehmenssitz Weiterstadt, Geschäftsführer Metin Dogan, Oliver Michel
participants (5)
-
Jochen Bern
-
lst_hoe02＠kwsoft.de
-
Martin Vegter
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Steffen Kaiser
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Tom Talpey