[fetchmail-devel] [Bug #18853] IMAP IDLE + SSL: Error: re-poll failed

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Bug #18853, was updated on 2013-Jan-03 22:49
Here is a current snapshot of the bug.

Project: fetchmail
Category: None
Status: Open
Resolution: None
Bug Group: None
Priority: 3
Submitted by: w-f
Assigned to : none
Summary: IMAP IDLE + SSL: Error: re-poll failed

Details: I use fetchmail with SSL and IMAP IDLE. The IMAP connection freezes after some time and the re-poll failed after 28 min. It looks like there is a ssl socket timeout before a IMAP IDLE re-poll is issued.

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Jan  3 20:31:35 mini2 fetchmail[14842]: IMAP> A0005 IDLE
Jan  3 20:31:35 mini2 fetchmail[14842]: IMAP< + OK
Jan  3 20:59:35 mini2 fetchmail[14842]: IMAP> DONE
Jan  3 20:59:35 mini2 fetchmail[14842]: re-poll failed
Jan  3 20:59:35 mini2 fetchmail[14842]: socket error while fetching from web...@fi...@imap.strato.de
Jan  3 20:59:35 mini2 fetchmail[14842]: 6.3.24 querying imap.strato.de (protocol IMAP) at Thu, 03 Jan 2013 20:59:35 +0100 (CET): poll completed
Jan  3 20:59:35 mini2 fetchmail[14842]: Query status=2 (SOCKET)
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The re-poll does not fail, when the idle timeout is reduced from 28 min to 10 minutes. This should also fulfil the RFC 2177, because the RFC suggests to re-issue a IDLE command at LEAST every 29 minutes.

RFC 2177 

   "The server MAY consider a client inactive if it has an IDLE command
   running, and if such a server has an inactivity timeout it MAY log
   the client off implicitly at the end of its timeout period.  Because
   of that, clients using IDLE are advised to terminate the IDLE and
   re-issue it at least every 29 minutes to avoid being logged off.
   This still allows a client to receive immediate mailbox updates even
   though it need only "poll" at half hour intervals."

Other IMAP Clients uses a shorter IDLE re-poll timer or issues a NOOP Command.
Microsoft Outlook:  10 min
Apple Mail:  IMAP NOOP every 1 minute (RFC 3501: "The NOOP command can also be used to reset any inactivity autologout timer on the server.")

------
Patch (Reduce  idle_timeout  to 600)
diff fetchmail-6.3.24-patched/imap.c fetchmail-6.3.24/imap.c 
718,719c718
< 	/* mytimeout = idle_timeout = 1680; */ /* 28 min */
<         mytimeout = idle_timeout = 600;  /* reduce to 10 min to prevent ssl socket timeout */
---
> 	mytimeout = idle_timeout = 1680; /* 28 min */


Enviroment:
fetchmail 6.3.24
OS:  Mac OS 10.7.5
IMAP Server:  Provider Strato (imap.strato.de)

---
Best regards,
Wolfgang


Follow-Ups:

Date: 2013-Jan-03 23:02
By: m-a

Comment:
Have Strato fix their server timeouts instead, the 30 minute timer is a "MUST" clause in RFC-3501 section 5.4, see http://tools.ietf.org/html/rfc3501#section-5.4

If there is a socket timeout, I'd like to see an strace or truss trace proving it, and possibly an accompanying tcpdump or wireshark/tshark dump of the protocol with timestamps, to see when the connection gets closed. Chances are that there is a problem on your end - are you using IPv4 NAT or Masquerading?
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For detailed info, follow this link:
http://developer.berlios.de/bugs/?func=detailbug&bug_id=18853&group_id=1824