This guide will show you how to enable the queuelifetime option in Plesk. This is a file that defines how long your server will attempt to process or deliver an email before bouncing it to the originating sender defined in the header of the email message.
1. Access your (dv) as the root user via SSH.
2. Run the following commands, one at a time. These commands create the queuelifetime file and then restarts qmail.
echo "259200" > /var/qmail/control/queuelifetime
/etc/init.d/qmail restart
When the maximum time has been met, the message will bounce.
TIP:
The value in this file must be in seconds. Here are some examples you can use:
- 86400 (one day)
- 259200 (three days)
- 432000 (five days)
http://kb.mediatemple.net/questions/1559/Enabling+queuelifetime+for+qmail#dv