postfix-commands.md

Useful Postfix commands for debugging and monitoring

Sending and receiving mails

• Sending test mail: echo "Testing" | mail -s "Testing Mail" yourname@gmail.com
• Reading incoming messages: mail navigation: https://unix.stackexchange.com/questions/26790/what-is-mail-and-how-is-it-navigated

Handling pending queue

• see messages in queue: mailq or postqueue -p
  • Delete messages in mailq: postsuper -d ALL

Checking logs or debugging any email

• inspecting particular message in queue: postcat -vq XXX_MESSAGE_ID
• Seeing error logs:
  • tail -f /var/log/mail.err
  • /var/log/mail.log | grep error
• for generating summary of logs: pflogsumm /var/log/mail.log -d today
• Checking logs for particular email: cat /var/log/mail.log | grep user@email.com

Configuration related

• Check postfix conf: postconf
• For default settings: postconf -d
• Check postfix differences from default: https://gist.github.com/robinsmidsrod/1339247

cd ~/
postconf -d >postfix.defaults
postconf >postfix.conf
diff -u postfix.defaults postfix.conf | grep -v '^ '|grep -v '^@' |grep -v '^---' | grep -v '^+++'

• Change host name via (updates system hostname): sudo hostnamectl set-hostname mail.mydomain.com