How to achieve E-Mail Notification on root login?

[Matthias Petermann]

Hello,

given there is a FreeBSD system with users in the wheel group, what is  
the best practise
to send out a notification via E-Mail if one of them becomes root via  
su? In an ideal
case the E-Mail would contain the user name and the time.

I thought about using sudo but this is not in the base system which I  
would prefer.

Kind regards,
Matthias


-- 
Matthias Petermann <matthias at d2ux.org>