Posts Tagged ‘queues’

How to list and delete mail queue on Qmail / Sendmail / Postfix and Exim SMTP server

Wednesday, April 3rd, 2013

How to list and manage delete Qmail Postfix Sendmail Exim mail SMTP queue View-and delete manage Linux and FreeBSD mail server queue

I have to administrate different kind of mail servers. Different clients has different requirements so in daily job I had to take care for all major mail server platforms our there. Often I have to fix problems with mail servers one very useful thing is to check the mail server queue to see what is there holding to be delivered. Often problems with busy mail servers are rooted in overfilled queues with undelivered mails so checking the queue on Postfix / Exim / Sendmail and Qmail is among the first thing to do to diagnose a problem with improperly working SMTP. In this little article I will show how one can check what is in the queue even if he didn't have the technical background on how each of those mail delivery agents works.

1. How to check and manage queue of Qmail Mail Server

Essential info on how many messages are in the queue and to list this messages in Qmail are done with qmail-qstat and qmail-qread.

a) Checking how many messages are in Qmail queue undelivered to remote SMTPs

root@mail:~# qmail-qstat
messages in queue: 1
messages in queue but not yet preprocessed: 0

b) Listing undelivered e-mails held in Qmail queue

root@mail:~# qmail-qread
26 Mar 2013 01:33:07 GMT  #9609259  748  <>

One other useful command in dealing with Qmail queue is qmail-qread type it and see for yourself what it does.
c) Flushing qmail queue

Use a tiny shell script ( ), deleting all files in /var/qmail/queue/mess – directory where qmail stores undelivered messages in queue.

# ./

Though above script should be working in some cases, where there are permission problems with Queue or some other mess it is better to use more sophisticated Qmail Queue cleaining tool Qmail MailRemove. To use its necessary to have a working version of Python programming language. Once downloaded Qmail MailRemove, mkdir  /var/qmail/queue/filter (a directory needed for MailRemove to work). Then run script

# ./ email_to_remove

Other variant to clean messed qmail queue is to use qmailHandle.

2. How to check and delete mails from queue in Postfix SMTP

On postfix queue is checked using both postqueue command which is postfix's specific tool for viewing the queue or the standard sendmail mailq. mailq is actually – Postfix to sendmail compitability interface, i.e. this command is not the native way to view queue in Postfix but is just a wrapper binary which invokes postqueue with an option to visualize what is in queue for SMTP admins accustomed to work with sendmail.

a) Checking list of undelivered e-mails

Below is an examples:

mail:~# mailq

-Queue ID- –Size– —-Arrival Time—- -Sender/Recipient——-
4A22BBE1A3*     657 Mon Apr  1 18:46:01

25824BE18B*     660 Thu Mar 28 18:15:03

D2AA7BE1BF      652 Sun Mar 31 04:30:21
(host[] refused to talk to me: 421 Too many concurrent SMTP connections; please try again later.)

mail:~# postfix -p
-Queue ID- –Size– —-Arrival Time—- -Sender/Recipient——-
36911BE18D*     662 Mon Mar 25 11:08:01

C2439BE207*     662 Fri Mar 22 14:59:45

4A22BBE1A3*     657 Mon Apr  1 18:46:01

b) Checking the  number of undelivered mails living in Postfix queue

postfix:~#  postqueue -p|wc -l

c) Viewing content of specific mail held in Postfix queue

Whether you need to check content of specific undelivered mail kept in queue you should do it by its ID, to view last mail from earlier postfix -p example:

postfix:~# postcat -q 4A22BBE1A3

*** ENVELOPE RECORDS deferred/A/4A22BBE1A3 ***
message_size:             656             187               1               0             656
message_arrival_time: Tue Apr  2 14:25:34 2013
create_time: Tue Apr  2 14:25:35 2013
named_attribute: rewrite_context=local
sender_fullname: www-data
*** MESSAGE CONTENTS deferred/A/4A22BBE1A3 ***
Received: by postfix (Postfix, from userid 33)
        id AA379BE07A; Tue,  2 Apr 2013 14:25:34 +0100 (BST)
Subject: =?UTF8?B?QWNjb3VudCBpbmZvcm1hdGlvbiBmb3IgU09DQ0VSRkFNRQ==?=
X-PHP-Originating-Script: 1000:register_login_functions.php
Content-type:text/plain; charset=UTF8
Message-Id: <>
Date: Tue,  2 Apr 2013 14:25:34 +0100 (BST)

Please keep that email. It contains your username and password for postfix.
nick : hawtiene
pass : 1v7Upjw3nT

*** HEADER EXTRACTED deferred/A/4A22BBE1A3 ***
*** MESSAGE FILE END deferred/A/4A22BBE1A3 ***

d) Deleting mails in Postfix queue

To delete all mails in Postfix queue run:

postfix:~# postsuper -d ALL

If Postfix cannot deliver a message to a recipient it is placed in the deferred queue.  The queue manager will scan the deferred queue to see it if can place mail back into the active queue.  How often this scan occurs is determined by the queue_run_delay.
The queue_run_delay is by default 300s or 300 seconds. If you have a very busy mail server you may see a large deferred queue.
To delete all mails in deferred queue.

postfix:~# postsuper -d ALL deferred

3. How to check mail queue of Exim mail server

Viewing number of messages and list of undelivered messages in Exim queue is done using exim command by specifying arguments.

a) Checking the list of undelivered mails kept undelivered in Exim SMTP Queue


root@iqtestfb:/etc/exim4# exim -bp

4d 416 1UI1fS-00021I-1s <root@ETC_MAILNAME> *** frozen *** 4d 746 1UI1gc-00023T-0S <root@ETC_MAILNAME> *** frozen *** root@ETC_MAILNAME 4d 752 1UI1lR-0003H0-89 <root@ETC_MAILNAME> *** frozen *** root@ETC_MAILNAME 4d 894 1UI1lR-0003H5-I6 <www-data@ETC_MAILNAME> *** frozen *** www-data@ETC_MAILNAME

b) Counting number of Exim undelivered messages kept in Mail Queue
exim-smtp:/etc/exim4# exim -bpc 2063 c) Getting a summary of all messages in Exim Queue (Count, Volume, Oldest, Newest, Destination Domain)
exim-smtp:/etc/exim4# exim -bp| exiqsumm

Count Volume Oldest Newest Domain —– —— —— —— —— 1 862 22h 22h 2 1751 12h 5h 21 3111KB 4d 3h 2 766KB 42h 7h 1 383KB 7h 7h 1 383KB 4d 4d 1 383KB 3d 3d 2 766KB 20h 19h 1685 3291KB 4d 1m etc_mailname 1 383KB 70h 70h 1 383KB 66h 66h gaaa 81 22MB 4d 15m 1 564 3d 3d 1 383KB 3d 3d 1 383KB 64h 64h 33 10MB 4d 2h 25 9193KB 4d 79m 1 383KB 4d 4d hotmailcom 2 1128 24h 20h 2 766KB 67h 67h 11 3831KB 3d 7h 1 383KB 20h 20h 3 767KB 37h 3h 6 1916KB 67h 45h 1 552 28h 28h 1 383KB 67h 67h 1 383KB 67h 67h 1 383KB 33m 33m 2 389KB 56h 4h 1 383KB 66h 66h 1 383KB 39h 39h 1 562 7h 7h 1 383KB 4d 4d 2 1116 49h 47h 1 383KB 28h 28h 1 383KB 3d 3d 75 31KB 4d 3d 1 572 3d 3d 1 383KB 71h 71h 1 383KB 28h 28h 1 383KB 14m 14m 36 11KB 4d 3d 1 557 53h 53h 1 383KB 23h 23h 1 383KB 4d 4d 2 766KB 67h 44h 1 383KB 42h 42h 1 549 3d 3d yahoo 43 9213KB 4d 74m 2 766KB 70h 46h 1 383KB 71h 71h ————————————————————— 2068 76MB 4d 1m TOTAL


c)  List Exim queued messages sorted by recipient address and sender address

  To list e-mails in queue sorted by recipient address

exim-smtp:/etc/exim4# exim -bpr|grep -Eo "^\s*[^ ]*@[^ ]*$" |sort | uniq -c

To List queued messages grouped by address of sender
exim-smtp:/etc/exim4# exim -bpr | grep -Eo "<[^ ]*@[^ ]*>" | sort | uniq -c  

d) Forcing Exim  to attempt re-send e-mails kept inside

As Exim is relatively new SMTP its authors thought deeply before writting it and included options to do queue e-mail sent whether server is not under extremely high loads as well as send, regardless of load. Make Exim start sending queue e-mails if server is not overloaded (no extra-high server load)
exim-smtp:/etc/exim4# exim -q -v

  To make Exim force a queue run regardless of system load exim-smtp:/etc/exim4# exim -qf -v  

To make Exim deliver only e-mails sent from server to server (usually e-mails from local server monitoring software and log reports)
exim-smtp:/etc/exim4# exim -ql -v

e) Deleting e-mails from Exim mail queue

To Remove a message from queue identify by ID

exim-smtp:/etc/exim4# exim -Mrm <message-id>     Force Exim delivery of a message regardless of Frozen status

exim-smtp:/etc/exim4# exim -M<message-id >  

f) Removing Exim mails older than certain seconds or hours To remove all mails older than 12hrs (43000 seconds) exim-smtp:~# exiqgrep -o 43000 -i | xargs exim -Mrm

Deleting all frozen mails from queue is done with:

exim-smtp:~# exiqgrep -z -i | xargs exim -Mrm  

Removing all e-mails belonging to particular sender

exim-smtp:~# exiqgrep -i -f | xargs exim -Mrm

  Removing all mails from a sender that are older than 12hrs

exim-smtp:~# exiqgrep -o 43000 -i -f | xargs exim -Mrm

g) Flushing Exim mail queue

exim-smtp:~# runq

exim-smtp:~# exim -q

4. How to view and manage sendmail SMTP queue

a) Listing all e-mails stored in Sendmail queue

To list the mail queue in sendmail

sendmail:~# sendmail -bp
/var/spool/mqueue is empty
        Total requests: 0


sendmail:~# mailq

/var/spool/mqueue (3 requests) —–Q-ID—– –Size– —–Q-Time—– ————Sender/Recipient———– m9TMLQHG012749 1103 Thu Oct 30 11:21 <apache@localhost.localdomain> (host map: lookup ( deferred) <> m9TMLRB9012751 37113 Thu Oct 30 11:21 <apache@localhost.localdomain> (host map: lookup ( deferred) <> m9TMLPcg012747 240451 Thu Oct 30 11:21 <apache@localhost.localdomain> (host map: lookup ( deferred) <> Total requests: 3

b) Checking queue for specific mail sender or recipient

sendmail:~# mailq | grep -i -A 2 -B 2

c) Removing all e-mails from Sendmail queue

To delete everything stored in Sendmail queue delete files from directory where sendmail stores still undelivered mails. In sendmail this is /var/spool/mqueue and /var/mqueue

sendmail:~# rm /var/spool/mqueue/*.*
sendmail:~# rm /var/mqueue/*.*

Deleting all pending mails from queue

To remove / delete e-mails originating from certain domain / user or recipient

sendmail:~# sendmail -qS -v

To delete e-mail from certain user or recipieint

sendmail:~# sendmail -qR -v


How to fix a broken QMAIL queue with queue-repair and qmhandle

Friday, May 27th, 2011

How qmail works, qmail queue picture :)

The aim of this small post is to give just a brief idea of how I fix my qmail server after breaking it or in case it is broken after mail bomb attacks, etc.

Most common cases when I break my qmail queue myself, are after I’m implementing some new patches and reinstall parts of the qmail server with a patched version of default qmail binaries.
On other occasions, I simply used the qmailctl to start or stop the server as a part of some routine tasks necessery for the administration of the qmail server.

Everybody who has already experience with qmail should have experienced, that qmail is very fragile and could break even with a simple changes, though if it works once it’s rock solid piece of mail servant.

Below I explain few ways I used through my days as a qmail sys admin to deal with broken or messed queues.

1. Fixing a broken qmail queue using automatic tools There are few handy tools which in most cases are able to solve issues with the queue, one very popular one isqueue-repair – check
Installation of qmail-repair is dead easy, but it needs to be installed from source as no official debian package is available:

linux:/usr/local/src# wget
linux:/usr/local/src# tar -xzvvf queue-repair-0.9.0.tar.gzdrwxr-xr-x charlesc/qcc 0 2003-10-22 16:54 queue-repair-0.9.0/
-rw-r--r-- charlesc/qcc 268 2003-10-22 16:54 queue-repair-0.9.0/TODO
-rw-r--r-- charlesc/qcc 1700 2003-10-22 16:54 queue-repair-0.9.0/CHANGELOG
-rw-r--r-- charlesc/qcc 18007 2003-10-22 16:54 queue-repair-0.9.0/COPYING
-rw-r--r-- charlesc/qcc 1098 2003-10-22 16:54 queue-repair-0.9.0/BLURB
-rwxr-xr-x charlesc/qcc 26286 2003-10-22 16:54 queue-repair-0.9.0/

To check if there are issues fixable within the qmail queue it’s as easy as:

linux:/usr/local/src# cd queue-repair-0.9.0
linux:/usr/local/src/queue-repair-0.9.0# ./queue-repair -t
checking files...
checking queue/mess files...
checking split locations...

The tool will walk through the mail sub-directories containing mail queued files in /var/qmail/queue and will list any issues found.
It’s recommended that the qmail server is stopped before any queue modify operations are issued on the server:

linux:/usr/local/src# qmailctl stop

Further on in order to solve any found issues with the queue, there is the “-r”/repair option:

linux:/usr/local/src/queue-repair-0.9.0# ./queue-repair -r

Another tool which comes handy whether a repair of a messed qmail queue is needed is qmhandle

The use of qmhandle is also pretty easy, all one has to do is to follow the usual classical steps of a download the source & compile:

linux:/usr/local/src# wget
linux:/usr/local/src# tar -zxvvf qmhandle-1.3.2
linux:/usr/local/src# cd qmhandle-1.3.2

Once again it’s necessery that the qmail server is stopped via its init script before qmHandle tool is used, e.g.:

linux:~# qmailctl stop

There is a difference between qmail queue repair tool and qmail handle , while qmail queue-repair tool is used to fix improper permissions of queued files with the qmail queue, qmhandle ‘s application is to completely delete the stored mail contents of a broken queue.

Deleting all the qmail queue content is in some cases the only option to fix the queue.
Often such a drastic measure is required after a heavy mail server overload, let’s say a result of spammers or caused by virus infected mail users which send a massive amounts of spam mails.

Thus at many cases when queue-repair was unable to solve a queue mess, I use qmhandble and sacrifice all the queued emails by completely wiping them out like so:

linux:/usr/local/src/qmhandle-1.3.2# ./qmhandle -D

Above command would eradicate all queued emails. Hopefully after the qmail server gets launched again with qmailctl start all the mail server operations should be back to normal.

Note that the use of qmhandle’s queue delete capabilities is pretty dangerous, if you forgot to stop the qmail server before issuing the above command!

Note that in order to use both qmHandle and queue-repair tools you will need to install python interpreter as both of the tools are written in python.

To check what is currently in the queue in Qmail, there are also native tools available, as you should probably know if you have dealt with qmail, e.g.:

debian:~# qmail-qstat
debian:~# qmail-qstat
messages in queue: 2
messages in queue but not yet preprocessed: 0

Often when there are problems with Qmail and more specificly with qmail server queue the qmail-qstat command does show messages in queue, however when an attempt to check what kind of messages are in the queue with qmail-qread no messages are shown, for instance below you see an example of that, even though qmail-qstat claims 2 messages are in the queue, qmail-qread is unable to list the messages:

debian:~# qmail-qread

If all is fine with qmail queue above’s qmail-qread command should have returned something similar to:

debian:~# qmail-qread
26 May 2011 07:46:47 GMT #659982 3517 <>
26 May 2011 07:46:47 GMT #659983 3517 <>

2. Fixing qmail queue manually This is very dangerous initiative, so before you try anything, make sure that you know what you’re doing, the possibility that you make the situation worst if you attempt to tamper manually the qmail queue is quite high 🙂

However if you’re still convinced to try fixing it manually, take a look at /var/qmail/queue it’s very likely that there are permission issues with some of the queued files, in order to fix the situation it’s necessery that the following directories:


gets explored with midnight commander / mc or some kind of convenient file explorer.

If there are queued files owned by users different from qmailq and user group qmail , for instance if owned by the root user, a simple chown qmailq:qmail to the wrong permissions file, should be able to resolve the issues.

Apart from all I explain above, there are many other ways suggested online on howto clean a qmail queue, one very popular one is using James’s qfixq shell script.

This script as of this very date is not working on Debian based systems, the script is dedicated initially to run on Fedora and Redhat based Linuces

Moreover myy experience with qfixq was never successful.

One very important note which is often a cause of many problems, is always make sure you stop and start the qmail server with an interval of at least of 10 seconds.

I’ve managed many servers which after an immediate (undelayed) qmailctl stop and qmailctl start was unable to run the whole engine of the qmail server (and either email sending or email receiving was not properly working) afterwards.

In that cases many weird behaviours are common, consider this seriously if you deal with the qmail-queue, it might happen that even if you have fixed your qmail queue, after a restart the qmail might breaks up.
I’ve experienced this kind of oddities numerous times, thus when I do changes to qmail I always make sure I restart the server a couple of times (at least 5 times 😉 ) always with a good delay between the HUPs.

And as always with qmail prayer is always needed, this server is complex, you never know what will happen next 🙂