Exim

Exim is a mail transfer agent (MTA) used on Unix-like operating systems. Exim is free software distributed under the terms of the GNU General Public License, and it aims to be a general and flexible mailer with extensive facilities for checking incoming e-mail.

Exim has been ported to most Unix-like systems, as well as to Microsoft Windows using the Cygwin emulation layer. Exim 4 is currently the default MTA on Debian GNU/Linux systems.

A large number of Exim installations exist, especially within Internet service providers and universities in the UK. Exim is also widely used with the GNU Mailman mailing list manager, and cPanel.

In March 2017 in a study performed by E-Soft, Inc., approximately 57% of the publicly reachable mail-servers on the Internet ran Exim.

Logs

The main exim log location is

   /var/log/exim_mainlog

This log governs sending and receiving of email.

The main log for email account access is

   /var/log/maillog

Check exim for unique email sent out

   sudo cat /var/log/exim_mainlog | grep "A\=dovecot_login" | awk -F"A=dovecot_login:" {'print $2'} | cut -f1 -d' ' | sort | uniq -c | sort -n | awk {'print $1, " unique emails sent by " , $2'} | grep EMAILADDRESS

Count messages in queue

    exim -bpc

Check messages in queue

    exim -bp

Check message Headers - message has to be in queue

    exim -Mvh MESSAGE ID 
         Example: exim -Mvh 1ggpHd-00070u-96

Check message body - message has to be in queue

    exim -Mvb MESSAGE ID 
         Example: exim -Mvb 1ggpHd-00070u-96

Save a Spam / message sample

    exim -Mvh MESSAGE ID > message.txt; exim -Mvb MESSAGE ID >> message.txt