Postfix Tips and Tricks

Inspecting Postfix’s email queue

list of queued mail

Including deferred mail and pending for delivery.

command:

mailq

The command 'postqueue -p' does the same thing as 'mailq'

queue processing

process entire queue now

postqueue -f

The command 'postqueue -f' does the same thing as 'postfix flush'

Schedule immediate delivery of all mail that is queued for the domain foo.com

postqueue -s foo.com

delete / clear the queue now

postsuper -d ALL

postsuper -d messageid

selective delete from queue

postsuper -d ALL deferred

inspecting queue

You can view the specific message in queue if you have the id

postcat -vq F276B2C0EA8 > themessage.txt

Replace 'F276B2C0EA8' with the postfix id of your message.

qshape prints Postfix queue domain and age distribution information.

qshape active

shows the number of emails being sent to each domain and how long they have been in the active queue

qshape deferred

shows the number of emails in the deferred queue for each domain and how long they have been there

Your installation may not have qshape compiled by default. qshape does not seem to be included with the Redhat / Fedora / Trustix / CentOS postfix packages. It needs to be added. For those distributions 'yum install postfix-perl-scripts'

Send Mail Test

check if postfix can send emails

echo "Hello this is a test." | mail -s "Testing" admin@foo.com

follow the message by watching the log - the -f follow tells tail to actively display log activity. Be advised there is a timeout in which tail will fail to follow.

 tail -f /var/log/mail.log

Determine Installed Version

If postfix is running and the main.cf specifies

smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu)

you can

telnet localhost 25

If postfix is not running you can check by the package.

There is no version switch on the postfix binary. Here are some ways you can determine what version of postfix is installed:

Redhat/Fedora/CentOS:

rpm -qa postfix

Debian/Ubuntu:

dpkg -s postfix