postqueue
Manage Postfix mail queue
SYNOPSIS
postqueue -p | -s site
PARAMETERS
-p
Display the entire Postfix mail queue. Equivalent to 'mailq'.
-s site
Display only those queue entries that are destined for the specified site. The site is typically the domain name of the destination. You can specify multiple -s options to view mail for different destinations.
DESCRIPTION
The postqueue command is a utility within the Postfix mail transfer agent (MTA) used to display the status of the Postfix mail queue. It provides a snapshot of messages currently awaiting delivery. Users can view message IDs, sender/recipient information, message size, and the reason why a message is being delayed. This tool is essential for diagnosing mail delivery problems, monitoring mail flow, and managing the Postfix mail system. It does not allow modifying queue contents or forcing immediate delivery of mail like `postsuper` or `postfix`. It's primarily a read-only tool. The output can be extensive on busy mail servers, providing insights into pending mail volume, enabling administrators to identify potential bottlenecks or misconfigurations contributing to delivery delays. Understanding the output requires familiarity with Postfix's internal queue structure and status codes. It is a critical tool for mail server administrators to monitor and troubleshoot email delivery issues.
QUEUE STRUCTURE
Postfix's queue is divided into several subdirectories, such as 'incoming', 'active', 'deferred', and 'corrupt'. The 'active' queue contains messages currently being processed. The 'deferred' queue contains messages that Postfix has temporarily failed to deliver and will retry later. Understanding these queues helps in interpreting the output of postqueue.
INTERPRETING OUTPUT
Each line in the output of postqueue -p typically represents a single message. The line will contain the message ID (a unique identifier), the message size, sender and recipient addresses, and any errors or warnings related to delivery attempts. Look for messages in the 'deferred' queue or messages with error codes to identify potential problems.
