pkg_add s-nail

cat > /etc/mail.rc <<EOF
set smtp-use-starttls
set smtp=smtp://smtp.sender.provider:587
set smtp-auth=login
set smtp-auth-user=sender@email
set smtp-auth-password=apppassword
set from="OpenSSH notifier <sender@email>"
EOF

cat > /etc/ssh/sshrc <<EOF
#!/bin/sh
client_ip="${SSH_CLIENT%% *}"
env | mailx -v -s "SSH login from $client_ip" your@email >/dev/null 2>&1
EOF

chmod a+x /etc/ssh/sshrc