[Solved] Comcast Residential ipv6 doesnt work

  • Hello,

    I get the following ip addresses:
    WAN- v6/DHCP6 2001:xx/128
    LAN- v6/t6 2601:xx/64

    Under LAN Interface settings, i have

    Track IPV6 Interface - WAN
    IPv6 Prefix ID - 0

    If i try to ping using Diagnostics>Ping using LAN interface it works,

    PING6(56=40+8+8 bytes) 2601:xx --> 2404:6800:4008:800::200e
    16 bytes from 2404:6800:4008:800::200e, icmp_seq=0 hlim=48 time=176.112 ms
    16 bytes from 2404:6800:4008:800::200e, icmp_seq=1 hlim=48 time=171.596 ms
    16 bytes from 2404:6800:4008:800::200e, icmp_seq=2 hlim=48 time=172.005 ms
    --- ipv6.l.google.com ping6 statistics ---
    3 packets transmitted, 3 packets received, 0.0% packet loss
    round-trip min/avg/max/std-dev = 171.596/173.238/176.112/2.039 ms

    However, on a LAN side client my ipv6 address is,
    inet6 fe80::xx  prefixlen 64  scopeid 0x20
    which doesnt match the 2601: entry.

    Also ping fails,

    ping6 ipv6.google.com
    connect: Network is unreachable

    Any idea how to fix this?

    Here are some screenshots of WAN and LAN settings.


  • I reinstalled pfSense and setup a basic LAN and WAN. Lo behold, my Lan client picked up an ip address.

    I created a few VLANS, setup a LAGG interface and introduced a Ubiquiti Edge switch in between router and the LAN client. I no longer get the ipv6 address.

    So, I guess there is something with either the VLAN or the switch which hoses my ipv6.

    Disabled IGMP Snooping on the switch and IPv6 is working fine. This seems to be known problem.

  • In your WAN settings, you want to request a different prefix size. With residential service, you can request as low as /60, which will give you 16 /64's to use on various networks.

    You will want to delete your DUID after changing the setting (you'll need to shell to the router and rm /var/db/dhcp6c_duid) then release/renew the WAN connection so it creates a new DUID and requests a new lease and prefix from Comcast's DHCPv6 server. Then you should be able to set up multiple networks using Track Interface and select a different prefix ID for each network.

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