Sendmail/ Postfix

MessageStats helps you better understand how Sendmail and Postfix perimeter servers are functioning in your messaging environment. Gather information and report on servers, incoming and outgoing message counts and identify which Internet domains are sending and receiving information to/ from your network. Reports include:

Server reports provide information about email usage on your servers, showing you which users are sending and receiving the most emails, the average amount of time each server takes to relay messages, server uptime and configuration statistics.

Message reports provide the number and size of messages received and transmitted by each server, including message sizes, recipients per message and rejected messages.
 
Internet reports document the communication with Internet domains as observed in log files, provide top internet domains, internal and external senders and receivers and external hosts.