Email duplication problem

[sbbobd]

Hi, I've been a happy user of ISPConfig for several years. (minor chord plays in background I'm using a Debian Sarge 3.1 installation setup via the appropriate 'perfect Debian setup'.

Recently a new problem with email started showing up. This problem manifests itself as duplicate emails in the users' inbox along with a lengthy wait as the users' email client app does its work. That is, the problematic emails are reread into the client's inbox each time the client logs into the mail server to check the mail.

The problem appears to be related to binary attachments, particularly ones that are >5Mb in size. The clients with these problems are setup to delete emails from the server as they are read. Thus, I can look at their inbox with a text editor or via 'mail -f /var/mail/webxx_username' and verify that the problematic emails (and subsequent emails in the inbox) are not getting deleted after they are read. After I manually delete the emails from their inbox, the duplication stops.

Perusing the boards here at HowtoForge leads me to believe it could be a file locking problem, though, like I said, I've been a happy user for years and this problem just started to show up and only on certail email accounts. My thinking on the locking issue is that the mechanism whereby the message is deleted from the client's inbox fails due to a locking problem, therefore the message doesn't actually get deleted.

My current effort to resolve this issue included enabling/disabled the 'MailScan' option in ISPConfig to stimulate a rewrite of the mail config files in hopes that that is the problem. This did not work.

How would I go about testing the locking mechanism to verify that it is or is not working correctly?

Any help would be greatly appreciated...

[till]

Thats a common problem with mail systems that use mbox format as mail storge. The best solution for this is to switch to the newer maildir format.

[sbbobd]

Okay, so I need to install courier-imap, courier-imap-ssl, courier-pop and courier-pop-ssl via apt-get.

Correct?

Then I simply check the 'Maildir' box in the ISPConfig...

[till]

Yes, thats correct. In case there are old mails stored in mbox format that have not been fetcehd yet by your customers, you will have to convert them to maildir format. This works e.g. with the command mb2md, you will find several threads about that in the forum incl. some helper scripts to automate the conversion.

[sbbobd]

Thanks a bunch for the emails on this thread, till.

I've now proven that Maildir works on a new install of ISPConfig.

Now I'm faced with updating a live server to switch from mbox to Maildir.

After I install courier-imap, courier-imap-ssl, courier-pop and courier-pop-ssl, will the mbox config work or do I have to switch to Maildir (in ISPConfig) to get mail up and running again. That is, are mbox and Maildir mutually exclusive?

Can I switch back and forth between mbox and Maildir without doing install/uninstall of packages?

Thanks sooo much,
sbbobd

[falko]

Originally Posted by sbbobd

do I have to switch to Maildir (in ISPConfig) to get mail up and running again.

Yes.

Originally Posted by sbbobd

That is, are mbox and Maildir mutually exclusive?

Yes.

Originally Posted by sbbobd

Can I switch back and forth between mbox and Maildir without doing install/uninstall of packages?

No.

[sbbobd]

If, due to some unforeseen consequence, the switch to Maildir fails, how do I return to mbox?

Do I rerun the Postfix/POP3/IMAP install steps? Or, is their a quicker way?

Thanks,
sbbobd

[till]

In that case you will have to install the old imap and pop3 daemon again.

[sbbobd]

The install of postfix is

apt-get install postfix postfix-tls libsasl2 sasl2-bin libsasl2-modules ipopd-ssl uw-imapd-ssl

Do I only need to reinstall ipopd-ssl and uw-imapd-ssl?

Thanks,
sbbobd

[falko]

Originally Posted by sbbobd

Do I only need to reinstall ipopd-ssl and uw-imapd-ssl?

Yes, that's right.