I'm baffled in the SF Bay Area as well. All was working just fine until last night. Got home to find that I can get to my ASUS (RT-AC68U) Wireless-AC1900 Dual-Band Gigabit Router but there was no Internet connection. Did the usual, rebooted the Xfinity CGM4140COM modem, waited and then rebooted the router. No joy.
Plugged directly to the Xfinity modem I get to the internet. But my Asus router status says, "Your ISP's DHCP does not function properly." We've had a bunch of outages in our area recently also. So baffled and frustrated with Xfinity at the moment. Nothing was changed during the day as I was out all day... Sad to see other posts without resolution.
If you are hanging a stand-alone / separate router off of the gateway device, and the gateway is not in *bridge mode*, you are cascading 2 routing devices which results in an undesirable "double NAT" condition on your home network.
Google "double NAT" for info about it's potential pitfalls.
You really should put it in to bridge mode. Here's how;
Thanks for taking the time to respond. However, it was in Bridge mode and it was working up until Thursday night.
I called Comcast today and spent about at least an hour if not 1.5 hours with two separate people to work through the problem. Unfortunately, the first guy, while nice enough, did not have the technical skills or tools to help me... so after 20 minutes he sent me to the "more technical" support person. She was lovely and smart and helpful. She could see that the DHCP was not working. After some time she was able to get it working from her end and a bunch of rebooting and resetting of both the XFi modem and my ASUS router. All this to say that it is now resolved. So it is possible to get it working. From the best that I can tell it WAS a dhcp problem at Comcast end and not an ASUS router problem. The settings on my router were fine and had the DHCP been working it would have worked.
Thanks... just wanted to close the loop for others who may have this problem.
Glad you got it squared away !