I've had this baffling issue throughout the house here of late; namely my wireless router, despite any indication to the contrary, not letting me on wifi. Of course the solution wasn't immediately apparent - I would just change wireless access points and get right back online - these things sometimes happens. But last night I decided to dig deeper into it and and that's when I discovered my iPad was on the wrong network entirely. Using the wrong default gateway, in an address space I'm not even running. Renew lease didn't work and I don't know how to flush the DNS cache on an iPad. I finally hardcoded the IP and after a couple of attempts got it to work.
This morning, when I couldn't get my work Mac to connect to VPN I ran an ifconfig and it was on the same errant network space??? # cat /etc/resolv.conf and I notice the domain is, "Belkin." I run a beefy Netgear Nighthawk X6 with no broadcast domain, so what in the hell is, "Belkin" doing handing out IPs on my network, and masquerading as as my SSID, SKYNET?
The lightbulb moment: Running out of physical connections downstairs while simultaneously running out of gigabit ethernet switches, I'd daisy-chained some random hub into my wired network downstairs. I didn't even have to go down there to look, I knew what I had done. I brought up the errant default gateway in my browser and sure enough it was one of Dorian's old wireless routers I was using as a newtorking switch wrecking havoc throughout the house.
I'm going to win this battle; I just factory reset it.