I keep noticing that my internet will go out for all of my devices unable to resolve the DNS server. Interestingly enough, I found the culprit causing this. My internet went out and while it was out, I noticed Steam started auto-updating a game. The update was working fine, nothing else. As soon as the download stopped, the internet started working again. I am just very confused as to why a Steam download is hogging up litterally all of my bandwidth? I have a Netgear C6300 Modem Router which is capable of speeds up to 1 Gbps and i'm on a 100 mbps plan? Is Steam just wrecking my internet somehow? Or is something else going on. This is very concerning as we are looking into getting rid of our TV service and streaming channels, but with the internet going down from a small update on Steam? That just wont work. It also seems to happen whenever I download anything else on Steam.
Sounds like your best move is to let Steam cool down for a while. Check their user forums and ask if anyone else is having the same problems.
Three separate possibilities just came to mind:
1) Does your Netgear C6300 include a QOS feature that prioritizes data from certain applications? They may call this 'feature' Upstream (gaming) QOS or Downstream (WMM) QOS. Either way, TURN THEM BOTH OFF!
2) Do you run any Google apps in the background, such as Mail, Calendar, or Drive? How about Microsoft Office, Outlook, or OneDrive? Many of these will try to synchronize your local computer datafiles with a remote database server. Try turning ALL of them off.
3) The Netgear C6300 combo gateway is designed around Intel's Puma-6 chipset, which is known to be full of software bugs. The extreme latency issues cause communications failures with the network's DNS servers. You may be able to return your unit or exchange for a different Netgear model that is NOT based on Puma6.