Hello @ohifra,
I found this thread:
https://community.nethserver.org/t/mailserver-stats/1498
- nethserver-awstats is available but we have to setup Mail stats, just works for virtual hosts actually I think:
https://wiki.nethserver.org/doku.php?id=awstats
- pflogsumm, a perl script for stats that may be sent by mail:
https://www.server-world.info/en/note?os=CentOS_7&p=mail&f=7