Courier-imap timeout trouble

[nvoth]

Hello,

We are seeing lots and lots of connections from blackberry.com coming in to IMAP and IMAPS on our servers. They seem to be persistent. In fact, I've see 30-40 connections on IMAP from blackberry that never seem to drop. I've even done a tcpdump on several of the connections and there's no data being passed. It seems that blackberry just connects and then never, (or rarely), drops.

Does anyone know how to change the default idle timeout in courier-imap so that the connections won't just sit there? I've looked through the configs and the docs and can't find any reference to it.

Thanks,

-Nick Voth

 

[FranklinT]

Disabling IDLE in courier-imap.

I had a similar problem with Apple Mail which has a configurable setting to use the IMAP IDLE functionality to stay logged in, periodically checking email. As the server in question was primarily used by Mac users, this caused imapd to run out of daemons and stop responding. One solution is, of course, to raise MAXDAEMONS in /etc/courier-imap/imapd, but you will eventually begin to tax your server's resources unduly.

The better solution is to disable IDLE entirely in /etc/courier-imap/imapd.

Change:

IMAP_CAPABILITY="IMAP4rev1 UIDPLUS CHILDREN NAMESPACE THREAD=ORDEREDSUBJECT THREAD=REFERENCES SORT QUOTA IDLE"

To:

IMAP_CAPABILITY="IMAP4rev1 UIDPLUS CHILDREN NAMESPACE THREAD=ORDEREDSUBJECT THREAD=REFERENCES SORT QUOTA"

... and restart courier-imap. This should prevent those pesky Blackberry (or Apple Mail) connections from persisting ad infinitum.

Hope it works for you!

Franklin

 

[nvoth]

That worked like a champ. Thanks very much! So far I don't see any down side and we've had no customer complaints.

-Nick Voth