Serious problem with mailbox lockup

Discussions on webmail and the Professional version.
Julian
Posts: 12
Joined: Thu Oct 20, 2005 12:36 pm

Serious problem with mailbox lockup

Post by Julian » Thu Oct 20, 2005 12:50 pm

I am running MailEnable Pro version 1.6 with all hot fixes applied on a Win 2K Server (also patched up-to-date) hosting 75 post office and 400 to 500 mailboxes.

All has been fine until around a week ago, since which we have been getting an increasing number of customers complaining that they cannot collect from their mailbox.

Upon investigation we have found that we can remove the larger mails waiting to be collected (all with attachments, sometimes spam, sometimes real) and then the customer can collect fine. Such mails vary from 35KB to 1MB and all customers are on fast DSL lines (and usually collect much larger mails without problem).

It seems like these mails are corrupt and therefore locking-up the mailbox. We have had two customers in the last four hours with this problem. I did recently install the "IMAP Remote Buffer Overflow" hotfix, and automatic Windows updates are enabled, but otherwise nothing has changed on the server.

Please can somebody urgently advise me on how to proceed with resolving this matter - it is driving me mad and we will start to lose customers soon.

Thanks

Julian

MailEnable
Site Admin
Posts: 4441
Joined: Tue Jun 25, 2002 3:03 am
Location: Melbourne, Victoria Australia

Post by MailEnable » Thu Oct 20, 2005 12:56 pm

1. Which protocol is locking up? IMAP or POP or all?
2. Does it lockup for all users or just some users?
Regards, Andrew

Julian
Posts: 12
Joined: Thu Oct 20, 2005 12:36 pm

Post by Julian » Thu Oct 20, 2005 1:03 pm

Locks up on POP collection for individual mailboxes.

MailEnable
Site Admin
Posts: 4441
Joined: Tue Jun 25, 2002 3:03 am
Location: Melbourne, Victoria Australia

Post by MailEnable » Thu Oct 20, 2005 1:25 pm

Is there anything reported in the POP Debug log file at the time of lockup?
Regards, Andrew

Julian
Posts: 12
Joined: Thu Oct 20, 2005 12:36 pm

Post by Julian » Thu Oct 20, 2005 1:29 pm

POP dubug logging was disabled - I have now enabled it and will post back when we get another lockup report. Sorry, I'm a bit new to fixing problems in MailEnable - it has run like a dream for the last couple of years.

Cheers

Julian

andyvm
Posts: 49
Joined: Thu Feb 05, 2004 8:56 pm

Post by andyvm » Fri Oct 21, 2005 2:36 pm

Make sure your virus software is not scanning your postoffices.

Julian
Posts: 12
Joined: Thu Oct 20, 2005 12:36 pm

Post by Julian » Tue Oct 25, 2005 8:40 am

Just realised that the problem is also occuring on a second server (running Mail Enable standard - can't give a exact version as the diagnose page will not display). This server has had no Mail Enable hotfixes applied in quite some time (probably not in the last 12 months). It has no antivirus or spam filtering.

The mails that are locking up mailboxes all seem to have attachments of PDF or JPG format. Any ideas on how to proceed?

Julian
Posts: 12
Joined: Thu Oct 20, 2005 12:36 pm

Post by Julian » Tue Oct 25, 2005 9:17 am

We have now isolated a mail that causes these problems and have been able to perform some tests. It is 187KB and has a JPG attachment. When placed in any mailbox and then an attempt to collect that mailbox is made, the collection is extremeley slow (0.5KB/min on a 1Mb ADSL line); collection times-out before completion. If the JPG is extracted from the mail using a text editor, the mail can be collected without problem.

winter
Posts: 26
Joined: Sun Apr 03, 2005 5:46 pm

Post by winter » Tue Oct 25, 2005 5:29 pm

This is the same problem I was having that I discussed in this thread...

http://forum.mailenable.com/viewtopic.php?t=8688

The easy way for me to fix it was to just delete the mail from the users mailbox. I figured it was a one time thing...I hope it is not something that I will see cropping up again.

Mark

PS-Was the email you were having trouble with from Amazon.com by chance?

Julian
Posts: 12
Joined: Thu Oct 20, 2005 12:36 pm

Post by Julian » Wed Oct 26, 2005 8:33 am

Has happened seven times across two mail servers in the last week. Isolating the problem mail from a mailbox with a hundred messages (mostly spam) can be pretty time consuming - we need a better solution!

I have a nastly feeling that the extremely slow collection rate is because the server has maxed out the processor and is causing problems for all services.

Julian
Posts: 12
Joined: Thu Oct 20, 2005 12:36 pm

Post by Julian » Thu Oct 27, 2005 3:42 pm

Just had another one - this is really frustrating for us and our clients; we need to prevent it happening, our only other option is to email all our hosting customers to advise what to do when it happens (which would be really unprofessional).

Any ideas anybody?

andyvm
Posts: 49
Joined: Thu Feb 05, 2004 8:56 pm

Post by andyvm » Thu Oct 27, 2005 4:23 pm

You said your second server has no antivirus "filter" running. Do they have antivirus software running on the actual server, and is it scanning your post offices or your queues. Exclude the whole mailenable folder from the realtime scanner.

What is the firewall setup?

Julian
Posts: 12
Joined: Thu Oct 20, 2005 12:36 pm

Post by Julian » Thu Oct 27, 2005 4:41 pm

The server is not running any form of AV software and is not firewalled. It is one of our dedicated servers used as a public shared hosting server.

andyvm
Posts: 49
Joined: Thu Feb 05, 2004 8:56 pm

Post by andyvm » Thu Oct 27, 2005 4:46 pm

Wow, not firewalled, that's scary...

Alright, lets look to the client end. Do you have multiple users reporting this? What have you replicated it with? MS Outlook? Do you have any local AV software?

If you can post the e-mail MAI file, I can pop it into my setup and give it a try as well.

Julian
Posts: 12
Joined: Thu Oct 20, 2005 12:36 pm

Post by Julian » Thu Oct 27, 2005 4:57 pm

The server is not firewalled as it runs a wide variety of services on different ports, it is locked down in every other way, and in over two years we have had no successful hacks (although attempts have been made).

Yes multiple users are reporting the same problem (different mailboxes in different postoffices). We have replicated the problem with MS Outlook, but customers have reported the same problem with Outlook Express and some weird Mac email client. Locally we have Avast AV (WinXP64) and Norton (WinXP Pro). Not sure on customers, but would expect all to have AV of some sort.

The problem mail that we have been testing with can be downloaded from:

http://www.future-shock.net/downloads/mail.zip

Unzip and drop it into a mailbox - watch collection crawl to a halt until timeout.

Many thanks for helping in this, it really is very appreciated.[/url]

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