RT-AC88U - Comcast / Xfinity - Your ISP's DHCP Does Not Function Properly

Hi All,

I wanted to post a solution I found out for this issue. I noticed during my troubleshooting that there were several posts on Reddit about this issue without a good solution posted.

1. Turn off both devices - Modem/Router (I was using a NetGear Cable Modem)
2. Turn on Modem - Connect directly via Ethernet bypassing router
3. Release & Renew your IP once the Modem is up. Confirm everything is working. This likely means that everything is A-Okay from Comcast's perspective. If it works - don't bother calling Comcast Tech Support they won't help you with the AC88U.
4. Turn on the AC88U - plug the ethernet back into the modem as expected. Connect over SSID or LAN (LAN Preferred).
5. (Optional) Factory Reset the Modem by holding down the small red button for 5+ seconds until the power light blinks. Give it about 10 minutes to reset.
6. Setup your AC88U as desired. (Auto IP, No Password for ISP, etc.)
7. Advanced Settings > Disable IPv6 (Unclear if necessary, but most folks are happy with 192.168.1.0/24)
8. Advanced Settings > WAN > DHCP query frequency > "Normal" (Also unclear if necessary, but...)
9. Advanced Settings > WAN > Hit 'Mac Clone'
10. My internet turned back on...pretty much instantly.

Hope this helps someone in the future.