cyrus 2.5 imap idle/stuck connections (DOS like)

[Wolfgang Breyha]

Heiler Bemerguy via Info-cyrus wrote on 07/03/2019 16:30:
> My  "man imapd.conf" doesn't list this option at all. I think my Cyrus 
> 2.5.10 is older than it..

Yes. It appeared in 2.5.11 according to my build environment.

But there already was the option
     timeout: 30
before. So every connection was closed by default after 30 minutes if there
was no activity.

"imapidletimeout" uses the value of "timeout" as upper limit default as well.

> But I've added it to the .conf anyway. Won't hurt if it doesn't exist 
> yet, right? lol
I currently don't remember if imapd ignores unknown options or fails on startup.

But maybe the better option is to use
tcp_keepalive: yes
anyway.

We had "dead" connections as well before imapidletimeout existed and I was
able to get rid of them by activating keepalives to trigger the "timeout: 30"
check.

Greetings, Wolfgang
-- 
Wolfgang Breyha <wbreyha at gmx.net> | https://www.blafasel.at/
Vienna University Computer Center | Austria