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Problem sending IMAP mail from Thunderbird

bettati

Problem sending IMAP mail from Thunderbird
« on: December 14, 2006, 05:17:16 PM »
I have SME Server 6.0.1 with ClamAV and SpamAssassin installed.
Spam filter is enabled.
Client use a local LAN connection to SME Server, using IMAP mailboxes and Mozilla Thunderbird as client.
Sometimes happens that when client try to send a mail, wait for a lot of time (20-30-40 seconds) and receive a message like:

- message delivering failed, message cannot be delivered ... SMTP MyServer...

Resending message 2 or 3 times goes fine.

IIf i disable 'SpamFilter' in Spam Filter Settings behaviour cannot reproduce and sending mail was very quickly, about 2 seconds.

What's wrong ?

Regards.
Andrea.

Offline Brenno

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Problem sending IMAP mail from Thunderbird
« Reply #1 on: December 15, 2006, 07:31:04 PM »
bettati,

This might not be that helpful, but I, too, am using 6.0.1 with both ClamAV and SpamAssassin installed and am experiencing timeouts when trying to send mail.  Some of my staff are still using Outlook Express, but many have already been migrated over to Thunderbird.   This affects both LAN and WAN users, though does not appear to be a problem using WebMail.  It appears that the email is, in fact, being sent however the problem lies in copying the email to the sent-mail folder.  This seems to be where the timeout is happening.

Unfortunately, because this is a production server, we are not in a position to disable ClamAV and run for a period for testing whether or not this has any impact on things.

My problem started after having the server crash with the "Drive exceeded Failure Prediction Threshold" error message which forced me to rudely reboot the server.  Since then, I've been monitoring the 4 SCSI drives in the box and have found that one of them runs 13 degrees hotter than the other 3.  I have not found an explanation for this yet.

Is anyone else having troubles such as this?

Offline Knuddi

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Problem sending IMAP mail from Thunderbird
« Reply #2 on: December 17, 2006, 07:42:23 PM »
Are you running on a single IP subnet or are the affected users maybe on a different IP net? If that is the case then see the last section on my OpenVPN Howto:

http://sme.swerts-knudsen.dk/index.html?frame=http%3A//sme.swerts-knudsen.dk/howtos/howto_30.htm

I have also seen long timeout when the server is doing Spam filtering on outgoing emails. Try to disable Clam for outgoing emails and see whether this affect the performance. The reason for Clam is the disabling clam for outgoing will also do the for SpamAssassin - well at least if its my installer you have used.

Rgds,
Jesper

Offline Brenno

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Problem sending IMAP mail from Thunderbird
« Reply #3 on: December 17, 2006, 09:09:49 PM »
Knuddi,

Thanks for the reply!  I did a bit more digging, and as a pre-emptive measure, I increased the concurrency limit to see if that's going to make any difference.  I will monitor things to see if this is partially or wholly to blame.  Failing that, I can disable the Clam for outgoing messages to check for any progress there.

To answer your question, we have four locations across the country, each with their own subnet, all connected via IPSEC VPN through Linux firewalls.  This system seems to work remarkably well.   Most users in remote offices access email via the public interface (WAN) to prevent any unneccessary clogging of the VPN tunnel, which runs on a separate DSL connection.  Since both WAN and LAN users were experiencing the timeouts, I didn't think it would be related to which interface or subnet they might be on or using.