howto's

Qmail queue is growing. How can I speed up process of sending mail?
Article ID: 1414
Last Review: Oct,6 2008
Author:
Last updated by: system
Resolution

Usually Qmail queue is growing due to too many messages in remote queue, because sending mail to remote servers takes
much more time than delivering the message to the local mailbox.

By default Qmail uses up to 20 ‘qmail-remote’ processes to deliver mail to remote servers. This value can be not enough
if the server has heavy mail traffic. In this case you can increase number of simultaneously running ‘qmail-remote’
processes by creating /var/qmail/control/concurrencyremote file with needed value, for example:

# echo 50 > /var/qmail/control/concurrencyremote

Then restart Qmail. See “man qmail-control” for more information. Also, see the articles about SPAM issue 766.
Keywords: big queue stuck mail slow delivery

How do I rebuild qmail queue if it is damaged or consists of a lot of spam messages?
Article ID: 252
Last Review: Mar,5 2009
Author: Vitaly Malakhov
Last updated by: Vitaly Malakhov APPLIES TO:

* Plesk 8.x for Linux/Unix
* Plesk 7.5.x Reloaded

Resolution

This instruction is written for RPM-based systems (RedHat, Fedora, CentOS, etc…).

Please perform the following steps to recreate Qmail`s queue.

Attention!

All current messages will be removed from the queue in this case and cannot be restored.

1. Stop Qmail and xinetd.

/etc/init.d/qmail stop
/etc/init.d/xinetd stop

2. Move current queue to another location.

mv /var/qmail/queue /var/qmail/queue_old

3 Reinstall ‘psa-qmail’ RPM to recreate qmail queue structure with the command like:

rpm -Uvh --force psa-qmail....

4.(Optional).Reinstall drweb-qmail RPM if you use DrWeb antivirus feature which comes with Plesk.

rpm -Uvh --force drweb-qmail....

5.Start Qmail and xinetd:

/etc/init.d/qmail start
/etc/init.d/xinetd start
Note: you should get the both psa-qmail and drweb-qmail RPMs from the same Plesk version distributive which is installed
on the server.
You can obtain current psa-qmail, drweb-qmail RPMs and Plesk build versions by running the following commands on Linux
systems:


rpm -q psa-qmail
rpm -q drweb-qmail
rpm -q psa

The server is saturated with SPAM. There are many messages in the queue. The mail is sent slowly.
Article ID: 766
Last Review: Mar,16 2009
Author: Daria Taranova
Last updated by: Daria Taranova APPLIES TO:

* Plesk 7.5.x Reloaded
* Plesk 9.x for Linux/Unix
* Plesk 8.x for Linux/Unix

Resolution
First check that all domains have the option ‘Mail to non-existing user’ set to ‘reject’ but not to ‘forward’. You can
change this setting to all domains using “Group Operations” in the “Domains” tab in Parallels Plesk Control Panel. The
option “Reject mail to nonexistent user” is available since Parallels Plesk Panel 7.5.3.

Also, please, check that all the IPs and networks in the white lists are reliable and familiar to you.

Check how many messages are in the queue with Qmail:

# /var/qmail/bin/qmail-qstat
messages in queue: 27645
messages in queue but not yet preprocessed: 82

If the queue has too many messages, try to discover the source of SPAM.

If mail is being sent by an authorized user but not from the PHP script, you can run the command below to find the user
that has sent the most messages (available since Plesk 8.x). Note that you must have the ‘SMTP authorization’ activated
on the server to see these records:

# cat /usr/local/psa/var/log/maillog |grep -I smtp_auth |grep -I user |awk '{print $11}' |sort |uniq -c |sort -n

The path to ‘maillog’ may differ depending on the OS you are using.

The next step is to use is “qmail-qread”, which can be used to read the message headers:

# /var/qmail/bin/qmail-qread
18 Jul 2005 15:03:07 GMT #2996948 9073 bouncing
done remote user1@domain1.com
done remote user2@domain2.com
done remote user3@domain3.com
....

This shows the senders and recipients of messages. If the message contains too many recipients, probably this is spam.
Now try to find this message in the queue by its ID ( # 2996948 in our example):

# find /var/qmail/queue/mess/ -name 2996948

Examine the message and find the line “Received” to find out from where it was sent for the first time, for example, if
you find:

Received: (qmail 19514 invoked by uid 10003); 13 Sep 2005 17:48:22 +0700

it means that this message was sent via a CGI by user with UID 10003. Using this UID it is possible to find the domain:

# grep 10003 /etc/passwd

If the ‘Received’ line contains a UID of a user ‘apache’ (for example invoked by uid 48) – it means that spam was sent
through a PHP script. In this case, you can try to find the spammer using information from spam email (address from/to
or any other information). It is usually very difficult to discover the source of SPAM. If you are absolutely sure that
this time there is a script which sends SPAM (tail grows rapidly for no apparent reason), you can use the following
script to know what PHP scripts are running at this time:

# lsof +r 1 -p `ps axww | grep httpd | grep -v grep | awk ' { if(!str) { str=$1 } else { str=str","$1}}END{print str}'`
| grep vhosts | grep php

You can also apply KB article which describes the procedure of discovering which domains are sending mail through PHP
scripts.

Lines in Received section like

Received: (qmail 19622 invoked from network); 13 Sep 2005 17:52:36 +0700
Received: from external_domain.com (192.168.0.1)

mean that the message has been accepted and delivered via SMTP, and that the sender is an authorized mail user.

Putty is an SSH/telnet/etc client which allows you to connect to remote servers such as a Linux or BSD webserver. When
you change directories etc in a terminal shell the window title in Putty is likely to change, depending on the shell’s
settings. This post looks at how to change the Putty window title to be what you want and how to prevent it changing as
you change directories.

The first screenshot below shows the Windows taskbar with several instances of Putty running. The default value is
usually something like the login name followed by the hostname and then the current directory. This can make it
difficult to know which window is which when wanting to bring up a specific open putty connection.
putty windows with default naming from the shell

It is usually possible in your server’s shell configuration to change what appears in the window title, but instead of
messing around with that you can do it in Putty instead.

Before logging in, make a couple of configuration settings changes and you can make the window title whatever you want
it to be. Select “Window” -> “Bahaviour” and then enter a name in the “Window Title”. In the example below I have
labelled it “webserver” but it can be anything you want. The title will appear in the window’s title area, the taskbar
button and in the Alt+Tab task switcher.
changing the window title with putty

The next step is to select “Terminal” -> “Features” and tick the box that is labelled “disable remote-controller window
title changing” as shown in the screenshot below. Without setting this option the window title is likely to change when
you change directories on the remote server.
prevent xterm from changing the window title

The final step is to save your settings so you don’t need to keep doing this each time. Go back to the main session
screen, enter a name into the “Saved Sessions” section and click the “Save” button as shown in the screenshot below.
save your session for next time

The final screenshot below shows some example names and how much easier it is to distinguish among the various Putty
windows open.
putty window titles with custom naming

It’s really easy to change the window title in Putty and makes it a lot easier to identify a particular server when, if
like me, you often have several of them open.

Ever perform a cat command on a binary file at the command
line? Usually, you get a screen full of bizarre characters, and
sometimes you end up with a terminal that.s unusable. Rather
than having to close the terminal and re-open it, just issue a
reset command:

reset

And, all should go back to normal. Sometimes the carriage
return may stop working in your terminal, in which case, you
need to do the following to make reset work:

<LF>reset<LF>

<LF> is the line-feed character, normally Ctrl-J.

If you ever need to download an entire Web site, perhaps for
off-line viewing, wget can do the job.for example:
$ wget \
--recursive \
--no-clobber \
--page-requisites \
--html-extension \
--convert-links \
--restrict-file-names=windows \
--domains website.org \
--no-parent \
www.website.org/tutorials/html/
This command downloads the Web site www.website.org/
tutorials/html/.
The options are:
--recursive: download the entire Web site.
--domains website.org: don.t follow links outside website.org.
--no-parent: don.t follow links outside the directory
tutorials/html/.
--page-requisites: get all the elements that compose the
page (images, CSS and so on).
--html-extension: save files with the .html extension.
--convert-links: convert links so that they work locally, off-line.
--restrict-file-names=windows: modify filenames so that
they will work in Windows as well.
--no-clobber: don.t overwrite any existing files (used in case
the download is interrupted and resumed).