Netgear router models are RAX45-100NAS and RAX54-100NAS

CrimpOn, thanks for your help with this!  How you can read someone else's network woes and make sense of it is quite impressive!

I do know that the 10.0.0.3 is my work laptop that I was using today to monitor the office router (RAX-45) logs looking for the precise moment the DoS attack began.  It is set up by my employer's IT group, and should be pretty secure.

However, on prior Tuesdays when this occurs (always around 12:25pm), I have been at work, so my work laptop could not possibly have been part of the equation for those days.

I have had similar thoughts that maybe one of my wifi devices was communicating on its on volition to the "cloud", but none of those devices are connected to my office router RAX45.  All those devices (smart thermostat, smart switches, phones, Roku, etc) are all on the living room router (RAX54) for that very reason.  I wanted to keep any "sketchy" wifi devices away from my secure ones by keeping on separate routers.

I'll check my Arris to have a look at its firewall.  Can you tell me what I should be looking for?

Also, the fact that both Netgear routers go down at the same time, same day, every week is intriguing to me.  It would seem there is some sort of schedule involved.  That first lead me to check the firmware updates, in case the updates are sent out at 12:20 pm every Tuesday and my routers stumbling on the update.  But, they are all up to date, as is my Arris.  My thermostats and cameras do communicate their data thru the router to the cloud, I guess, but again, they are on RAX54, so shouldn't affect RAX45 I would think.

I'm already learning from you, and though this isn't sorted yet, I very much appreciate your help!  Let me know what info you need from me.  I can get you router .cfg files, router event logs, etc.

Thanks,  Allen