How to avoid duplicate ssh authorization notification?

Question

SSH

Hello. There is a server running Ubuntu Server 14.04. It was necessary to organize an e-mail notification when a user is authorized via ssh. Now this is implemented by writing the following in /etc/ssh/sshrc:

echo $USER $(date) $SSH_CLIENT | mail -s "ssh login" [email protected]

It works, but the notification email comes twice. At the same time, notifications from fail2ban and mdadm come normally and are not duplicated. Help to understand - what could be the reason for duplication?