>From my memory, Outlook would keep two connections open, one kind of "background / new mail" one, and one for the open folder.
Our experience was that there were cases where flakey tcp paths could lead to long times for connections to die, though we were seeing it more with macbooks and apple mail than with Outlook. At one point we implemented a periodic untagged response to force a dead connection to die... but eventually we just moved to keeping track of the idle time on each connection and instead of blocking new connections, we would just kill the most idle one... though we would block a connection if there were no connections over a minimum idle threshold to prevent too many real connections from fighting for access. It's unfortunate that imap connections (at least ones that are in SELECTED state) are so heavy weight, otherwise we wouldn't need to care as much. Anyways, the point of my story is that it may not be a change to Outlook at all, but a Windows networking change or maybe just more network flakiness among your customers or even your own network (less likely). Brandon On Fri, Aug 7, 2020 at 8:34 AM Benoit Panizzon via mailop <mailop@mailop.org> wrote: > Hi Gang > > We use DoveCot as IMAP Server and have limited the number of > connections per IMAP account to 20 which looks to have been sufficient > in the past couple of years. > > Since about two weeks we get an increased number of users complaining > about IMAP connections problem and name (0x8...) error message which > outlook 2016 throws at them. > > When looking at the log, we see those users sometimes hit the 20 IMAP > connections limit. So we increased this limit to 50 connections per > user+ip and they still hit it. > > This ONLY happens with customers using outlook 2016. Any other clients > never hit this issue. > > So I wonder if Microsoft has rolled out some weird update for outlook > 2016 lately or if anyone could have a hint on what causes this issue > and how to solve. > > Mit freundlichen Grüssen > > -Benoît Panizzon- > -- > I m p r o W a r e A G - Leiter Commerce Kunden > ______________________________________________________ > > Zurlindenstrasse 29 Tel +41 61 826 93 00 > <+41%2061%20826%2093%2000> > CH-4133 Pratteln Fax +41 61 826 93 01 > <+41%2061%20826%2093%2001> > Schweiz Web http://www.imp.ch > ______________________________________________________ > > _______________________________________________ > mailop mailing list > mailop@mailop.org > https://chilli.nosignal.org/cgi-bin/mailman/listinfo/mailop >
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