Well I just went back to this old script, I rewrote so it will now work with Nagios.
The output is simple and just reports total Top emailers, the script also requires/takes 3 arguments
topemailers.vbs 3 5000 10000
would report only the Top 3 senders of yestarday and would raise alarm to Warning if TOTAL emails sent yestarday were 5000 and critical for over 10000.
The scriptauto downloads the required files (logparser.dll)
Note: NRPE_NT service must run under a exchange admin account, under local system it will not work.
More about the history of this script is here
Status OK 1116 – email@example.com(93) – firstname.lastname@example.org(558) – email@example.com(465)