How to check mail queue in centos

To check the mail queue in CentOS, you can use the following commands:

1. postqueue -p: This command shows the current mail queue, including the sender, recipient, and status of each message.

   postqueue -p

   This will display a list of messages in the queue, along with their status (e.g. "hold", "active", "deferred", etc.).

2. mailq: This command is similar to postqueue -p, but it provides more detailed information about each message in the queue.

   mailq

   This will display a list of messages in the queue, along with their sender, recipient, and status.

3. postsuper -s: This command shows the status of the mail queue, including the number of messages in the queue and the number of messages that have been deferred.

   postsuper -s

   This will display a summary of the mail queue, including the number of messages in the queue and the number of messages that have been deferred.

4. postcat -q: This command allows you to view the contents of a specific message in the queue.

   postcat -q <queue_id>

   Replace <queue_id> with the ID of the message you want to view. This will display the contents of the message.

5. sendmail -bp: This command shows the current mail queue, including the sender, recipient, and status of each message.

   sendmail -bp

   This will display a list of messages in the queue, along with their status.

Note: The postqueue and postsuper commands are part of the Postfix mail server, while the mailq command is part of the Sendmail mail server. If you are using Postfix, you can use the postqueue and postsuper commands. If you are using Sendmail, you can use the mailq command.