It should be one of these: > > bounce_queue_lifetime = 1d > maximal_queue_lifetime = 1d Hi, Thanks for your quick answer. I think it is maximal_queue_lifetime = 1d I got it from below URLs. http://www.postfix.org/rate.html *maximal_queue_lifetime* (default: 5 days) How long a message stays in the queue before it is sent back as undeliverable. Specify 0 for mail that should be returned immediately after the first unsuccessful delivery attempt http://archives.neohapsis.com/archives/postfix/2000-10/1271.html -- Thank you Indunil Jayasooriya -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.centos.org/pipermail/centos/attachments/20071130/736ac8a8/attachment-0005.html>