Alert when a new client logs onto the LAN

[aagaag]

Is there a way to instruct pfSense to send an alert when a new client logs onto the LAN?

(I have just moved to software pfSense [on a Hyper-V VM] from a Lancom router, and I am totally impressed with it. I am however just beginning to scratch the surface of what it can do, so please bear with me if I am asking something painfully obvious/naïve!)