Postfix

Some useful links to explain the concepts of Postfix

Concepts

Configuration

• http://blog.schaal-24.de/mail/postscreen-im-kampf-gegen-spam/?lang=en

• https://www.howtoforge.com/hardening-postfix-for-ispconfig-3

• https://workaround.org/ispmail/squeeze/postfix-domain-types

• https://workaround.org/article/postfix-database-configuration

• https://www.howtoforge.com/virtual_postfix_antispam

• https://rtcamp.com/tutorials/mail/

• https://www.linode.com/docs/email

• https://www.linode.com/docs/email/running-a-mail-server

SSL/TLS on Postfix

• https://blog.kruyt.org/postfix-and-tls-encryption/

Troubleshooting & Log Parsing

Queue Management

• http://www.postfix.org/QSHAPE_README.html

• https://easyengine.io/tutorials/mail/postfix-queue/

• http://wiki.zimbra.com/wiki/Managing_The_Postfix_Queues

• http://www.tullyrankin.com/managing-the-postfix-queue

• https://www.wirehive.net/blog/2014/11/07/5-top-tips-for-reviewing-your-postfix-mail-queue

Commands

• Sorting queued mails by From address

sudo mailq | awk '/^[0-9,A-F]/ {print $7}' | sort | uniq -c | sort -n

• Holding queued mails by From address

sudo mailq| grep '^[A-Z0-9]'| grep <sender-ID>| cut -f1 -d' ' | tr -d \*|sudo postsuper -h -

• Holding queued mails by To address

sudo mailq | tail -n +2 | grep -v '^ *(' | awk  'BEGIN { RS = "" } { if ($8 == "<recipient>") print $1 } ' | tr -d '*!' | sudo postsuper -h -

• Holding queued mails by Domain

sudo mailq| grep '^[A-Z0-9]'| grep @<domain>| cut -f1 -d' ' | tr -d \*|sudo postsuper -h -

• Holding emails from the [active|deferred] queue based on subject

sudo find /var/spool/postfix/[active|deferred]/ -type f  -exec grep -il '<subject>' '{}' \; | xargs -n1 basename | sudo postsuper -h -

• Removing Mails based on sender Address

sudo mailq| grep '^[A-Z0-9]'| grep <sender-ID>| cut -f1 -d' ' | tr -d \*|sudo postsuper -d -

• Removing Mails based on Domain

sudo mailq| grep '^[A-Z0-9]'| grep @<domain>| cut -f1 -d' ' | tr -d \*|sudo postsuper -d -

• Delete mails to a specific mail address

sudo mailq | tail -n +2 | grep -v '^ *(' | awk  'BEGIN { RS = "" } { if ($8 == "<recipient-ID>") print $1 } ' | tr -d '*!' | sudo postsuper -h -