What luck, I chose today to install a new piece of network gear. I thought I had managed to totally FUBAR my network. DNS was failing, "ping 1.1" (my current goto test "Am I connected to the internet?" as it requires the fewest keystrokes and hits the Cloudflare DNS 1.0.0.1) failed and I just assumed it was my fault. Backed out my changes, and discover in fact, the internet was down.