This script scans and compare ssh version and host keys with the previous records. It sends alert email when the ssh version or host key is different from last scan.
Python2.7, python-nmap, and the latest nmap. Nmap(version 6.47) comes with Debian Jessie won't work because a bug. Nmap that work well include version 7.40(from Debian Stretch) and 7.60(latest version as of Oct 2017).
Config the email setting in config.json, add target hosts, then run it either manually, or from cron.