Posts Tagged ‘imap connections’

Cause and solution for Qmail sent error “Requested action aborted: error in processing Server replied: 451 qq temporary problem (#4.3.0)”

Friday, October 28th, 2011

One of the qmail servers I manage today has started returning strange errors in Squirrel webmail and via POP3/IMAP connections with Thunderbird.

What was rather strange is if the email doesn’t contain a link to a webpage or and attachment, e.g. mail consists of just plain text the mail was sent properly, if not however it failed to sent with an error message of:

Requested action aborted: error in processing Server replied: 451 qq temporary problem (#4.3.0)

After looking up in the logs and some quick search in Google, I come across some online threads reporting that the whole issues are caused by malfunction of the qmail-scanner.pl (script checking mail for viruses).

After a close examination on what is happening I found out /usr/sbin/clamd was not running at all?!
Then I remembered a bit earlier I applied some updates on the server with apt-get update && apt-get upgrade , some of the packages which were updated were exactly clamav-daemon and clamav-freshclam .
Hence, the reason for the error:

451 qq temporary problem (#4.3.0)

was pretty obvious qmail-scanner.pl which is using the clamd daemon to check incoming and outgoing mail for viruses failed to respond, so any mail which contained any content which needed to go through clamd for a check and returned back to qmail-scanner.pl did not make it and therefore qmail returned the weird error message.
Apparently for some reason apparently the earlier update of clamav-daemon failed to properly restart, the init script /etc/init.d/clamav-daemon .

Following fix was very simple all I had to do is launch clamav-daemon again:

linux:~# /etc/inid.d/clamav-daemon restart

Afterwards the error is gone and all mails worked just fine 😉

How to fix “imapd-ssl: Maximum connection limit reached for ::ffff:xxx.xxx.xxx.xxx” imapd-ssl error

Saturday, May 28th, 2011

One of the mail server clients is running into issues with secured SSL IMAP connections ( he has to use a multiple email accounts on the same computer).
I was informed that part of the email addresses are working correctly, however the newly created ones were failing to authenticate even though all the Outlook Express email configuration was correct as well as the username and password typed in were a real existing credentials on the vpopmail server.

Initially I thought, something is wrong with his newly configured emails but it seems all the settings were perfectly correct!

After a lot of wondering what might be wrong I was dumb enough not to check my imap log files.

After checking in my /var/log/mail.log which is the default log file I’ve configured for vpopmail and some of my qmail server services, I found the following error repeating again and again:

imapd-ssl: Maximum connection limit reached for ::ffff:xxx.xxx.xxx.xxx" imapd-ssl error

where xxx.xxx.xxx.xxx was the email user computer IP address.

This issues was caused by one of my configuration settings in the imapd-ssl and imap config file:

/usr/lib/courier-imap/etc/imapd

In /usr/lib/courier-imap/etc/imapd there is a config segment called
Maximum number of connections to accept from the same IP address

Right below this commented text is the variable:

MAXPERIP=4

As you can see it seems I used some very low value for the maximum number of connections from one and the same IP address.
I suppose my logic to set such a low value was my desire to protect the IMAP server from Denial of Service attacks, however 4 is really too low and causes problem, thus to solve the mail connection issues for the user I raised the MAXPERIP value to 50:

MAXPERIP=50

Now to force the new imapd and imapd-ssl services to reload it’s config I did a restart of the courier-imap, like so:

debian:~# /etc/init.d/courier-imap restart

That’s all now the error is gone and the client could easily configure up to 50 mailbox accounts on his PC 🙂