ssh-notify
ssh-notify is a Go program, originally written in Bash, that sends a message to a Discord webhook whenever an SSH login occurs, and when the user logs out again.
The format of the message is as follows:
{hostname}: {user} logged in (remote host: {remote_ip}).
Configuration
To configure ssh-notify, copy the example config (ssh-notify.json.example) to the same directory. If your webhook URL is https://discord.com/api/webhooks/374355038877978415/jzR_6rd2USWNq2XdXvnfC5QCXaH7xxAKZDQCXaWh-w5H7xxFAuuIDlzPCSKuH7xxLFD3 then the WebhookId is 374355038877978415 and the WebhookToken is jzR_6rd2USWNq2XdXvnfC5QCXaH7xxAKZDQCXaWh-w5H7xxFAuuIDlzPCSKuH7xxLFD3. You can also configure ssh-notify to not notify for logins to certain users, useful if you have automated scripts logging into your servers.
You will also need to tell SSH to use ssh-notify. Do this by adding the following at the bottom of the /etc/pam.d/sshd file. Ensure that ssh-notify is executable.
session optional pam_exec.so /path/to/ssh-notify --config /path/to/ssh-notify.json