Sysadmin Blog

Postfix Mail Queue Cleaner

info@cyberbyte.ch (Mike Rhyner) — Mon, 14 Apr 2014 10:17:59 GMT

This small shell script removes all messages originating from a certain sender address out of the postfix mail queue.


#! /bin/bash
if [ "$1" == "" ]; then
  echo "please give e-mail address"
  exit 1
else
  emailaddr=$1
fi
for id in `mailq | egrep "[0-9A-F]{10} " | grep "$emailaddr" | cut -d " " -f 1`
do
  echo $id
  postsuper -d $id
done

Detect and block abuse of (cracked) e-mail account

info@cyberbyte.ch (Mike Rhyner) — Fri, 28 Feb 2014 09:45:39 GMT

To avoid bad things(TM) caused by a cracked e-mail account on our postfix mailserver, I used the script Check Auth Log to detect abnormal high numbers of logins or logins from many different IP addresses within a certain time onto a certain account. Then the script will lock out the account. This, together with per-session limits within postfix configuration (smtpd_client_message_rate_limit, smtpd_client_recipient_rate_limit), should help to avoid or at least mitigate the damage caused by cracked accounts, i.e. SMTP server being blacklisted.

Postfix Mail Queue Manager

info@cyberbyte.ch (Mike Rhyner) — Fri, 28 Sep 2012 22:00:00 GMT

Description

This PHP script shows the content of the mail queues of multiple servers and give you the possibility to hold, release, delete and reqeue single messages.

If you install a tiny wrapper script on mail servers, you may even remove or requeue multiple messages from a certain sender.

In addition, you can also requeue all messages (sendmail -q).

Download

Download the gzip'ped tar archive

Prerequisites:

On a web- or intranet accessible host (access protection highly recommended!):
- Web Server with PHP script language support (shell_exec function has to be enabled)
- Key-based SSH access to mail servers for webserver user

On mail servers:
- Postfix
- sudo

Installation

Unpack the archive beneath a webserver document root

Adapt the variables $mailservers and $user to your needs, if you like to use the selection by sender e-mail address feature, configure also variable $wrapper_cmd

Add the following lines to /etc/sudoers on the mail server(s), assuming user admin for login to the mail server(s) (change it to your needs):

admin    ALL=(ALL) NOPASSWD: /usr/sbin/postsuper
admin    ALL=(ALL) NOPASSWD: /usr/sbin/postqueue
admin    ALL=(ALL) NOPASSWD: /usr/local/bin/mailqueue.sh

(last line only needed for selection by sender address)

If you want to use the selection by e-mail address feature, put mailqueue.sh to some path on the mail server(s) and make it executable, e.g.:

cp mailqueue.sh /usr/local/bin/mailqueue.sh
chmod 755 /usr/local/bin/mailqueue.sh

Try it out using http://yourwebserver/mailqmgr/index.php