Ubuntu 20.04 Set Up Alert Email for SSH Access

Hi there,

One of the most straightforward ways would be to put the following in /etc/profile:

if [ -n "$SSH_CLIENT" ]; then 
    TEXT="$(date): ssh login to ${USER}@$(hostname -f)" 
    TEXT="$TEXT from $(echo $SSH_CLIENT|awk '{print $1}')" 
    echo $TEXT|mail -s "ssh login" you@your.domain 
fi

In case that you are not receiving the emails, you can follow the steps here on how to setup ssmtp with SMTP authentication:

https://www.digitalocean.com/community/questions/how-to-send-emails-from-a-bash-script-using-ssmtp

However this is not a bulletproof solution, what I would recommend is to follow the steps here on how to harden your OpenSSH service here:

https://www.digitalocean.com/community/tutorials/how-to-harden-openssh-on-ubuntu-18-04

Hope that this helps!

Best,

Bobby