How do I get someone to send a provisioning signal to my modem so it will work in bridge mode again

I've had the same problem for about a week now. @ComcastChe solved it as well, but I have been unable to come into contact with him. It looks like Comcast's customer service hasn't improved since I last had their intertnet service over a year ago.

Here's my post with a couple of solutions that you may want to try instead of calling or posting online ad infinitum in a vain attempt for a response from a rep who knows what they're doing: https://forums.xfinity.com/t5/Your-Home-Network/Your-ISP-s-DHCP-is-not-functioning-properly-ASUS-router/m-p/3380294 

What modem do you have? I was finally able to fix my WiFi issue (no thanks to the Comcast techs).

I have the Motorola MB8600 who, up to the point I fixed my issue, I thought worked fine. However, the modem was the source of my issue. The modem has four LAN ports: one accessible to the end user and three under a sticker that could be easily removed. I removed this sticker and connected three devices to it: the Asus RT-AX56U router in LAN 1, an unmanaged switch in LAN 2, and my brother's PC in LAN 3.

I ended up getting an internet connection to my PC (connected through the switch), but all other connected devices failed to do the same. My router indicated that it was a DHCP issue on the ISPs side (see attached picture) and that led me to believe it was the same issue experienced by others on this forum.

I tried many of the solutions provided to me in addition to updating the firmware on my router, but nothing seemed to work. While I was replacing the ethernet cables for the third time in an attempt to find the root of the problem, I decided to reboot the modem with only the Asus router connected to LAN 1. To my surprise, the router started working while all other devices that I connected after the router did not.

The problem ended up being that the modem supported just one LAN connection at a time regardless of what or how many ports were in use. That is how I was able to get an internet connection through LAN 2 for the switch and later for the router on LAN 1. I had assumed that just like my previous modems, this one would support more than one LAN connection because of it having more than one LAN port. It would have been great had the reps informed me of this to begin with so I would not have wasted their and my time.

In sum, my problem was that my modem with four LAN ports could only use one at a time. Instead of following the link in the getting started guide for more details, I assumed it's functionality based on previous experience with other modems. I proceeded to troubleshoot my internet connection woes based on this assumption that Comcast reps did nothing to dispel. They had me trying to contact Asus to reconfigure my router or replace it altogether or have a Comcast technician come take a look at it. They basically tried to sell me a service or have me go somewhere else to get me out of their hair instead of you know, giving me actual service. Although the blame falls squarely on me for holding such a misconceived notion of my modem's functionality, the Comcast reps I spoke to are partly to blame for not having corrected me. Instead of pointing me to different directions and trying to sell me a service, they should have done a proper rundown of my network setup that would have revealed my erroneous belief. Anyway, this has gone on long enough so I hope my failure helps you in finding your solution!

P.S. For those who also own the Motorola MB8600, here's the link that explains why those four ports exist and why you can't use more than one of them simultaneously: https://motorolamentor.zendesk.com/hc/en-us/articles/115010589128-FAQ-The-MB8600-has-four-Ethernet-ports-Can-I-use-these-for-connecting-more-than-one-device-  

I would like to know the secret for this, too. Multiple reboots of both my moduem and router have not solved the problem. I've also tried the ipconfig/renew trick without success.

Provisioning has nothing to do with it. Have you done this;

https://www.xfinity.com/support/articles/wireless-gateway-enable-disable-bridge-mode

Just to be clear, you're saying I need to enable bridge mode on my Comcast router to fix this problem, not on the Asus? I can confirm that bridge mode on the Comcast modem is currently disabled.

In the meantime, it would appear that the problem has solved itself. Our Asus router is back to working as usual this morning.

Your original post was unclear...

Be advised that 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 its potential pitfalls.

You really should put it in to bridge mode. Here's how;

http://customer.comcast.com/help-and-support/internet/wireless-gateway-enable-disable-bridge-mode

I appreciate your help in explaining this. First, an update: after working perfectly fine all day, the Asus router suddenly stopped providing internet access again, just like yesterday. When inquiring directly with the Asus router, we received the same error message as yesterday: "Your ISP's DHCP is not functioning properly." This link (https://forums.xfinity.com/t5/Your-Home-Network/Your-ISP-s-DHCP-is-not-functioning-properly-ASUS-router/m-p/3380294) described the same problem and suggested a provisioning request would solve the problem. That's how I ended up in this thread.

In response to @EG , I enabled the bridge mode as suggested, but it has not solved the problem. Do you have any other suggestions? Am I now in a position to benefit from a provisioning request?

Another update: The solution offered by @jmnsea  at the following page seems to have resolved the issue for me, at least for now. 

https://forums.xfinity.com/t5/Your-Home-Network/Your-ISP-s-DHCP-is-not-functioning-properly-ASUS-router/td-p/3377690

I only waited about 20 minutes between shutting everything down and starting it all back up, and I had to take one additional step, which was to go into my Asus router and change the DHCP query frequency to "Continuous mode," after everything came back online, because I still was receiving the "Your ISP's DHCP is not functioning properly" message.