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Spectrum/Charter IPv6 Prefix Length

keen155keen155 Posts: 3 Spectator
edited December 2022 in Spectrum Archives: 2020 - Present Jun 09, 2022

I am trying to setup IPv6 on my router connected to Spectrum. My router has multiple VLANs to isolate traffic with IPv4 now. I want to add IPv6 support for the network and VLANs.

What is the Prefix or Network length provided by Spectrum, /56, /60 or /64?

I cannot find any documentation or FAQs explaining what addresses the Spectrum DHCPv6 server gives out for residential customers. A /64 is not the recommended length since it cannot be subnetted for use with VLANs. I would prefer at least /60 which provides for 15 subnets.




  • RAIST5150RAIST5150 Posts: 893 Contributor
    Jun 09, 2022

    Seem to recall some chatter a couple years back about people trying delegation with /56. Think that is what I got to kinda/sorta work back then (Windoze and apps for it can be weird when it comes to IPv6)... but it was a good two years or more.

    It was being discussed off and on back before the site got revamped. IDK if you can successfully search for the threads.

  • RAIST5150RAIST5150 Posts: 893 Contributor
    Jun 09, 2022

    Googled it... and across the years, got a mix bag of results of /56 and /64... seems to vary by market, likely due to the gradual shift from TWC to Spectrum.

    Maybe some of the more recent reddit threads can give you some insight though if you want to put your Google Foo to the test.

  • keen155keen155 Posts: 3 Spectator
    Jun 09, 2022

    I appreciate your responses. I also had searched for that information on reddit and other sites. Like was mentioned, it probably varies by market. I guess I was hoping that someone technical from Charter/Spectrum would be watching the various posts and be able to officially answer how it was actually setup on their servers. I had tried the /60 which appeared to give my computers the right Prefix Delegation for one of the VLANs, though the VLAN could not get to any web sites. I have the Firewall rules on that VLAN to wide open for IP6. I will try the /56 just to see if that one works any better.

    This guessing gets frustrating. With more people adding IPv6 to their networks, I would have thought the FAQs and documents on ISP web sites would get updated so their customers can understand how IP6 is setup from the ISP. perspective.


  • ShirBlackspotsShirBlackspots Posts: 6 Spectator
    Jun 12, 2022

    You're kind of wasting your time. Spectrum disabled native IPv6 on their network approximately three weeks ago. Now the only thing that works is 6to4 Tunnel.

  • keen155keen155 Posts: 3 Spectator
    Jun 14, 2022

    ShirBlacksp. thanks for you feedback. I am not sure which Spectrum site you are in, though the Charter/Spectrum site in the St Louis area is running IPv6 right now. I have no problem running IPv6 addresses if I assume a /64 Prefix Delegation. I have been trying a /60 Prefix Delegation and it currently is working for a couple of my VLANs. I only am trying IPv6 on 2 of my VLANs in addition to the basic LAN interface. so that I don't waste my time if the /60 Prefix Delegation starts failing to connect to the internet. All the VLANs I have work fine with IPv4. I am just trying to test and learn more about IPv6 since it is becoming more popular with sites on the internet.

  • ShirBlackspotsShirBlackspots Posts: 6 Spectator
    Jun 19, 2022

    I believe I am in the Dallas/Fort Worth area.

  • HomeAdminHomeAdmin Posts: 12 Participant
    Jun 21, 2022

    I am in Ohio and for years I am getting a /56 prefix. No problem with IPv6 here in Ohio, working perfectly fine.

  • OhioGuy71OhioGuy71 Posts: 1 Newcomer
    edited July 2022 Jul 17, 2022

    I just looked at the DHCPv6 response and see that my delegated prefix is a /64. So unfortunately for me, this means no (easy) IPv6 on my guest VLAN. A /60 would be nice (allowing for 16 VLANs/subnets).

    I am in Southwest Ohio. To give an idea of what market I'm in, the reverse DNS records for my IPv4 and IPv6 IP addresses end in * (Kentucky?) and *, respectively.

    This person says they get a /56 (jealous):

This discussion has been closed.