IPv6 w/ Comcast and multiple nets not working



  • Hi!

    I figured I should probably jump on IPv6 now since it's been out for awhile and I have some free time on my hands.  I have Comcast residential service and pfsense 2.3.1.  I have multiple subnets…five all together.  One is for servers, wireless internal, visitor, workstations, and the default 'lan', which isn't used.  I enabled the following:

    WAN
    General:
    IPv6 Configuration Type  DHCP6

    DHCP6 client configuration:
    DHCPv6 Prefix Delegation size /56
    Send IPv6 prefix hint Check this box

    Servers
    General:
    IPv6 Configuration Type  Track

    Track IPv6 Interface:
    IPv6 Interface WAN
    IPv6 Prefix ID 1

    Before I did anything, I was getting an IPv6 IP on the WAN, and still am.  I'm also able to ping6 www.google.com on the pfsense console and I get responses back.

    However, I am not getting an IPv6 address on my "Servers" interface and my workstation isn't receiving an IPv6 address.  The address my workstation (on the servers subnet) is getting is...

    fe80::4fd:7a97:9912:cd28/64

    Do I also have to do something with the DHCPv6 Relay or DHCPv6 Server+RA?

    Thanks in advanced...



  • OK…I got it figured out...

    Going through the dhcp server logs, I found:

    "invalid prefix length 60 + 8 + 64"

    I did a bit more research and flipped the 56 prefix size to a 60.  Once doing this, I was able to get a DHCPv6 address on the workstations/servers and now able to ping google.

    So, either Comcast doesn't support a /56 or I need my DHCP reservation to expire so I can get an updated one.



  • Unless it's changed recently, the /56 is available on their business class service and the /60 is for residential.



  • @darkcrucible:

    Unless it's changed recently, the /56 is available on their business class service and the /60 is for residential.

    Thanks.  I thought I read somewhere that /56 is available on their residential service too, but the answer seems to be all over the place.  I'll have to play with this a bit more later on…



  • I'll validate darkcrucible's statement as well… /56 for business, /60 for residential, both for cable internet service. The only Comcast residential offering that offers a smaller prefix is their Gigabit Pro 2Gbps active fiber service, where they give a /48.



  • @virgiliomi:

    I'll validate darkcrucible's statement as well… /56 for business, /60 for residential, both for cable internet service. The only Comcast residential offering that offers a smaller prefix is their Gigabit Pro 2Gbps active fiber service, where they give a /48.

    A touch off-topic, but are there 16 subnets in a /60, where each subnet contains 254 hosts?



  • @wiz561:

    @virgiliomi:

    I'll validate darkcrucible's statement as well… /56 for business, /60 for residential, both for cable internet service. The only Comcast residential offering that offers a smaller prefix is their Gigabit Pro 2Gbps active fiber service, where they give a /48.

    A touch off-topic, but are there 16 subnets in a /60, where each subnet contains 254 hosts?

    You're thinking IPv4.
    A /60 gives you 16x /64 IPv6 subnets. So 2^64 addresses in each.


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