Managing a Postfix Queue - Commands

Show messages in queue: postqueue -p

Display message: postcat /path/to/postqueue/messageID

Delete a message: postsuper -d (queue ID)

Delete ALL messages: postsuper -d ALL

Attempt delivery of a message: postqueue -i (queue ID)

Attempt delivery of all mail queued for a particular site: postqueue -s (site)

Attempt delivery of all messages (flush): postqueue -f

Put mail "on hold" (stop delivery attempts): postsuper -h (queue ID)

Release mail that was put on hold: postsuper -h (queue ID)

Show various postfix queue stats: qshape
More on qshape