IPv6/Comcast Issues with Tracking WAN



  • First, I had lightning hit nearby. This took out my modem, as well as my NIC in my pfsense box. I put together a new pfsense box, but decided to start from scratch this time with the config instead of restoring the old one. The new box is running as usual. Everything's normal for IPv4. IPv6 is not behaving as it should, though.

    I have a /128 IPv6 address on WAN, as expected. When I go to my LAN/OPT1/OPT2 etc. interfaces, I can choose to track WAN and I get 0 - f for IPv6 Prefix ID. What this tells me is that there's 16 /64's available, (/60), but I am not getting an IP per interface. Only WAN has IPv6. Been through the settings quite a few times looking for something I forgot to set, cannot find anything.

    I do not have any advanced configuration set in the dhcpv6 settings for WAN, as I did not have any set before the change in hardware, where all this worked just fine. The modem is different, it's the Comcast modem, not one I own. That is different than before when it worked. I have gone in and deleted /var/db/dhcp6c_duid & /var/db/wan_cacheipv6, then rebooted the modem and the router, nothing changes.

    Any help would be appreciated.



  • @johnnybinator No backups? Any way you can recover the old config to restore or at least compare?



  • Make sure the Comcast "modem" is in Bridge mode, because it isn't likely just a modem. It's more likely a gateway (modem + router + WiFi). Comcast provides gateway devices these days so they can also provide their "xfinitywifi" network expanding their public WiFi coverage. Which is why I'll never rent a device from Comcast anymore.



  • @virgiliomi said in IPv6/Comcast Issues with Tracking WAN:

    Comcast provides gateway devices these days so they can also provide their "xfinitywifi" network expanding their public WiFi coverage. Which is why I'll never rent a device from Comcast anymore.

    Does that service actually use some of your bandwidth? Or is it a separate service that happens to be in the same box?



  • Comcast says that it's separate bandwidth, not counting against the speeds you're paying for and also not counting against the data limit they impose in some parts of the country. They use a different "service ID" (I think that's what it's called) for provisioning it to keep it separate.



  • @virgiliomi
    Then why's it such a problem?



  • It itself isn't... but the fact is that they're providing a gateway, and unless you put it in Bridge mode, it's acting as a router rather than a modem. So pfSense is getting a single WAN address and no prefix because it's being treated as a client on the gateway's network.


Log in to reply