Need Help From Comcast Representative on IPv6 Support

@XfinityDena​ To be fair, the IPv6 support was always unstable at best. With the previous modem, XB3 I believe, I would need to restart the modem to obtain a new IPv6 IP, which might last for a couple hours before disappearing. The new modem, model XB7-T, was swapped in about a week ago, and I haven’t detected a single successful IPv6 address on the WAN interface yet. The Comcast modem and my personal router have been restarted. I use bridge mode on the modem. My router has been configured to try automatically negotiate an IPv6 connection and also DHCP. DHCP worked with the previous modem. 

@user_0m5n3o Not all Gateways have access to use Ipv6. Here is a link with an overview of the Gateways https://www.xfinity.com/support/articles/broadband-gateways-userguides Are you able to swap to get an XB8?

@XfinityDena​ Hi, I don't think it is true that not all modern gateways have access to IPv6. As stated by xfinity here, https://www.xfinity.com/support/articles/about-ipv6, "You won't need a new Comcast device when your area makes the switch to IPv6.".

The nationwide rollout of IPv6 began in 2011-2012, https://corporate.comcast.com/comcast-voices/ipv6-deployment-technology.

As of 2016, "98 percent of the cable modems we provide to customers are managed over an IPv6-only connection." https://corporate.comcast.com/comcast-voices/world-ipv6-launch-four-years-later-taking-stock-and-looking-forward

Furthermore, the XB7 modem firmware has sections dedicated to IPv6 addressing: Gateway > Connection > Local IP Configuration. 

To troubleshoot further, I did a factory reset on the modem by pushing the WPS button for 60 seconds and connected a computer directly to the modem. After it came back up, I confirmed the modem received a global IPv6 address, and offered a Stateful DHCP address assignment to LAN devices on a /64 subnet. I reenabled bridge mode, and reconnected my router on port 1. I am now receiving IPv6 within my network and all IPv6 tests are passing. 

Thank you for your response. Have a great day. 

@user_0m5n3o Thank you for that information. I was going by the overview of our Gateways. I am happy the factory reset allowed you access. If you have any additional questions you can reach out to the Digital Care Team at any time as we are here 24/7 for your convenience. We are a digital team dedicated to assisting customers with all aspects of their account needs from troubleshooting together to billing inquiries and more. We are available over Xfinity Forums 7 days a week between 6:00 am - 12:00 am EST. Please have a safe and healthy weekend!