Source
r/PFSENSE•
boxsterguy

Anybody else on Comcast no longer able to get IPv6 prefixes?

Sometime in the past couple of days I've lost the ability to get prefix delegation from Comcast. I've tried calling support, but they're obviously useless.

Jun/17/2015 23:14:35: receive advertise from fe80::213:5fff:fe05:4be2%igb0 on igb0
Jun/17/2015 23:14:35: get DHCP option client ID, len 14
Jun/17/2015 23:14:35:   DUID: ... removed by me
Jun/17/2015 23:14:35: get DHCP option server ID, len 14
Jun/17/2015 23:14:35:   DUID: 00:01:00:01:17:32:3d:56:14:fe:b5:d6:e7:76
Jun/17/2015 23:14:35: get DHCP option IA_PD, len 72
Jun/17/2015 23:14:35:   IA_PD: ID=0, T1=0, T2=0
Jun/17/2015 23:14:35: get DHCP option status code, len 56
Jun/17/2015 23:14:35:   status code: no prefixes
Jun/17/2015 23:14:35: get DHCP option preference, len 1
Jun/17/2015 23:14:35:   preference: 0
Jun/17/2015 23:14:35: get DHCP option DNS, len 32
Jun/17/2015 23:14:35: server ID: 00:01:00:01:17:32:3d:56:14:fe:b5:d6:e7:76, pref=0

dhcp6c_wan.conf:

interface igb0 {
    send ia-na 0;   # request stateful address
    send ia-pd 0;   # request prefix delegation
    request domain-name-servers;
    request domain-name;
    script "/var/etc/dhcp6c_wan_script.sh"; # we'd like some nameservers please
};
id-assoc na 0 { };
id-assoc pd 0 {
    prefix ::/60 infinity;
    prefix-interface igb1 {
            sla-id 0;
            sla-len 4;
    };
};

The fact that the DHCP server returns "no prefixes" when asked for IA_PD with a prefix hint of /60 seems to me pretty obvious that it's on Comcast's end, especially since I made no changes to my WAN. I did play around with setting up an outbound VPN interface last weekend, but I don't really see how that would prevent IPv6 prefix delegation.

Anybody else having issues?

Posted Jun 18, 2015, 6:45 AM UTC

64
adancingbear•

I just double checked my config and I'm not having issues with comcast's ipv6, but I'm in Houston and it is a big network.

2
taev•

I can't help you specifically, but I work in the cable industry and can tell you that each community within a city that Comcast serves can have it's own configuration, so it's possible you need to talk to your Comcast office.

1
boxsterguyOP•

It ultimately got solved ... somehow. I had support reset my modem a couple of times, and then eventually one of those times releasing and renewing DHCP finally got IPv6 again (I suspect this was just coincidence and behind the scenes Comcast finally fixed their broken DHCPv6 server that was refusing prefixes, but of course Comcast will never own up to it being their issue).

Multiple calls, multiple reboots, multiple release/renew cycles, and a ticket submitted to the pfsense devs, and it just fixes itself randomly. Sometimes I think idiots are running Comcast's network, because this kind of stuff should be very deterministic.

The real WTF here is that every time the Comcast support techs felt out of their depth, they pawned me off to a support.com number. And of course support.com said there was nothing they could do, because they handle customer equipment issues which this very clearly was not. So I got stuck in phone tag hell, trying to get somebody to own up to it being their problem. And the usual approach of tweeting @comcastcares didn't get any response, either.

1
taev•

There are very few people who really know how the network works, and none of them have power over the whole thing (the responsibility is divided between several parts). Those guys are so busy that I doubt they talk to their support people, let alone you. Glad you got it fixed.

1