Re: DOS attack
Suggest you Google "dos attack teardrop or derivative" and start looking at all those references. Also for PORT 0.
HERE is a long one to read.
I've seen some claim it is an iPhone causing it?
You also have posted this in the wrong forum. This is soley for Netgear Nighthawk Routers, not Cable Modem/Routers. You should probably post over at https://community.netgear.com/t5/Cable-Modems-Routers-and-DSL/ct-p/en-home-dsl-and-cable-modems where you might get better help on this issue in the proper sub-forum.