DoS attack: Smurf

Hello guys.
I have the Netgear R6250
I have this unusual activity that's been going on for quite some time now and I really don't know how to address it. I keep getting hit with[DoS attack: Smurf] attack packets in last 20 sec from ip [150.222.240.255] this comes in. It different days and different times. I have a total of 12 so far and it's always the same address. I'm having a hard time believing that this is a false positive. Considering how many I have, any suggestions on what this is and how to stop it.

Appreciate your help or suggestions.
Ray