Every six months or so, COX DNS stops resolving hostnames. And I can't just change the DNS on the router to update every ipod, iphone, computer, server, virtual machine, game console, coffee maker and embeded video device. So on top of not understanding why DNS stops responding in the first place, I also don't understand why I can't just update the DNS in the router. All my DHCP devices are set to get their address and DNS from it.
No, I have to update each device manually. I use OpenDNS when I do. I have NS1 and NS2 IPs memorized. So two dozen or so device changes. Then, around six months time, OpenDNS stops resolving hostnames. I have to touch all devices again and point them at the router. This has happened, on average, every 6-months since I moved here in 2010.
I used to call COX. Funny thing, COX employs no network engineers. They would send some cable guys out and tell me, "Yep, dB levels are strong."
"That's not the problem I'm having," I would say, and explain domain name resolution. None of that mattered to them, because the dB levels were strong. Once they suggested I replace the router. I did. No change.
Its not the fact that it happens every six months, its that I don't know why, and that no one can explain it to me.