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Monday, December 16, 2013

Exim cheat sheet

Exim is a powerful mail transfer agent (MTA) used on many Linux servers. When emails can't be delivered immediately, they get put into a "queue." Managing this queue is crucial for server health and ensuring mail delivery. This guide provides quick commands for common Exim queue tasks.


CLEARING THE EXIM MAIL QUEUE

Sometimes, you need to clear out stuck or unwanted emails from the queue.

  • Remove All Mails: This command directly deletes all files from the input directory of the Exim spool, effectively clearing the entire queue. rm -rf /var/spool/exim/input/*

  • Delete All Frozen Mails: Frozen emails are those that Exim has temporarily stopped trying to deliver due to issues. exim -bpr | grep frozen | awk {'print $3'} | xargs exim -Mrm Alternatively, a more concise command: exiqgrep -z -i | xargs exim -Mrm

  • Delete Frozen Mails Older Than a Day: This is useful for clearing old, stalled messages without affecting newer ones. The 86400 represents seconds (1 day). exiqgrep -zi -o 86400 | xargs exim -Mrm You can change 86400 to any number of seconds for a different time frame.

  • Clear Spam Mails: If your logs indicate messages are marked as [SPAM]. grep -R -l [SPAM] /var/spool/exim/msglog/*|cut -b26-|xargs exim -Mrm

  • Clear Frozen Mails (Based on Log Entry): grep -R -l '*** Frozen' /var/spool/exim/msglog/*|cut -b26-|xargs exim -Mrm

  • Clear Mails for Unverified Recipients: grep -R -l 'The recipient cannot be verified' /var/spool/exim/msglog/*|cut -b26-|xargs exim -Mrm

  • Remove Mails from a Specific Sender (e.g., 'root'): Replace "" with the sender's email address or username, for example, root@yourhostname. exim -bp |grep ""|awk '{print $3}'|xargs exim -Mrm

  • Remove 'nobody' Mails: These often come from scripts. Replace HOSTNAME with your server's hostname.

    • From a specific sender (nobody@HOSTNAME): exiqgrep -i -f nobody@HOSTNAME | xargs exim -Mrm

    • For a specific recipient/domain (nobody@HOSTNAME): exiqgrep -i -r nobody@HOSTNAME | xargs exim -Mrm

  • Delete Mails for a Specific Domain: Replace yourdomain.com with the actual domain. exim -bp | grep "yourdomain.com" | awk {'print $3'} | xargs exim -Mrm


DELIVERING MAILS FROM THE QUEUE

If emails are stuck but should be delivered, you can force a delivery attempt.

  • Force Deliver All Mails: This command attempts to deliver all messages in the queue. The -P 40 option attempts 40 deliveries in parallel. exim -bpru |awk '{print $3}' | xargs -n 1 -P 40 exim -v -M

  • Flush the Mail Queue (Force Another Run): This tells Exim to process the queue again. exim -qff Alternatively: /usr/sbin/exim -qff exim -qf

  • Force Deliver Mails of a Particular Domain: Replace domain.com with the target domain. exim -v -Rff domain.com

  • Force Deliver a Specific Message: Replace MSGID with the message's unique ID. exim -M MSGID To view the transaction during delivery: exim -v -M MSGID


CHECKING THE EXIM MAIL QUEUE STATUS

These commands help you monitor the queue and inspect individual messages.

  • Exim Queue Summary: Provides details like count, volume, oldest, newest message, and domain breakdown. exim -bp | exiqsumm

  • Number of Frozen Mails: exim -bpr | grep frozen | wc -l

  • Total Number of Mails in Queue: exim -bpr | grep "<" | wc -l A simpler alternative: exim -bpc

  • View Mail in Queue for a User/Sender: Replace $name with the username or email address. exim -bp|grep $name

  • Check All Mails in the Queue: This lists all messages and their IDs. exim -bp

  • View Log for a Message: Replace message ID with the actual ID. exim -Mvl message ID

  • View Message Header: Replace $MSGID with the message ID. exim -Mvh $MSGID

  • View Message Body: Replace $MSGID with the message ID. exim -Mvb $MSGID


ADVANCED EXIM TOOLS

  • Simulate SMTP Transaction: This command helps debug Exim's checks, ACLs (Access Control Lists), and filters without actually sending a mail. Replace 127.0.0.1 with the IP you want to simulate from. exim -bh 127.0.0.1

  • Most Used Mailing Script Locations: This can help identify scripts sending a lot of mail. grep cwd /var/log/exim_mainlog | grep -v /var/spool | awk -F"cwd=" '{print $2}' | awk '{print $1}' | sort | uniq -c | sort -n

  • Check Syntactic Errors in Configuration: Use this when modifying Exim's configuration file. exim -C /config/file.new -bV

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