Here are a few handy items for Postfix email server users:
1. If your system is acting as a spam / antivirus / relay server for secondary internal servers, and your destination mail server is down, postfix will queue your messages to resend at a later time. In order for postfix to instantly re-queue these messages you use:
2. The mailq equivilant specific to postfix is
3. If you want to delete specific messages in your queue, use an ncurses based open source software called pfqueue. It will give you a menu that shows mail currently queued, and allows you to delete specific emails.