Just a simple script to notify by email of some login on the SSH server.
The dependencies are geoiplookup, s-nail, systemd, pam so make sure you have those.
If you are on Debian:
apt install geoip-bin geoip-database s-nail
Download the script and place it on /opt/ssh-login-send-mail.sh then configure it with your SMTP parameters then
chown root:root /opt/ssh-login-send-mail.sh && chmod 700 /opt/ssh-login-send-mail.sh
Then edit the pam configuration at /etc/pam.d/sshd adding the following row in @include common-session
session optional pam_exec.so seteuid /opt/ssh-login-send-mail.sh
Just login in your SSH server :D
You can just find some output in systemd, for example:
journalctl --since "10 minute ago" | grep "ssh-login-send-mail"