Got IPv6 Working on Cisco DPC3941B

[pgfitzgerald]

I decided to come back to this after some time and got it all working. I hope this helps folks.

I have a Cisco DPC3941B and a Ubiquiti EdgeRouter Lite

I have a static IPv4 block (/29) and a static IPv6 block (/56)

My delegated prefix is 2603:xxxx:xxxx:d000::/56

My gateway is using 2603:xxxx:xxxx:d000::/64

I am able to perform prefix delegation for 2603:xxxx:xxxx:d0e0::/59

Attempts to use larger prefixes fail

That still gives me 32 /64 subnets (2603:xxxx:xxxx:d0e0::/64 - 2603:xxxx:xxxx:d0ff::/64)

eth0 = WAN

eth1 = LAN

eth2 = WLAN

Here is the basic config that worked for me.

interfaces {
  ethernet eth0 {
    address 75.xxx.xxx.129/29
    dhcpv6-pd {
      pd 0 {
        interface eth1 {
          host-address ::1
          service slaac
        }
        interface eth2 {
          host-address ::1
          service slaac
        }
        prefix-length 59
      }
      prefix-only
      rapid-commit disable

    }

  }

}

You could keep going and configure specific PD options, stateless DHCPv6, IPv6 firewall rules, etc. Hopefully this will get you started.

[Veddy254]

PfSense has it a bit different in that the LAN has to be statically set, but I too get the /59.

EDIT: Also, I'm able to do stateful DHCPv6 through that method as well. If there are people who would like the steps I used to do that, I can post them. I haven't done any prefix delegation though and I suspect that I'd have to have another PFsense box in order to do that reliably, but I could be wrong.

[CEO_EASYSIMPLEIT]

Hi Veddy254,

I have been trying to get IPv6 working on my IPsense enviroment, If you could post your steps I would appreciate it.

Thank you

[Veddy254]

Sadly, it seems to have quit and I'm not sure why. I will parse through my logs here and try to figure out why it crapped out.

EDIT: So it seems to break after a week and I think I finally figured out why. My way seems to have involved temporarily doing a LAN - Track Interface -> WAN with PD-ID 0 and then swapping over to static which works... until the DHCP lease runs out on the DPC3941B for the original prefix request via Track Interface.

EDIT #2: BREAKTHROUGH! Logged into the gateway device and set the DHCP lease time to Forever (DISCLAIMER: now if the modem reboots, this likely will crap out but at least it's an easy albeit bothersome fix.) Had the LAN interface pick up Prefix ID 0 via Track Interface -> WAN. Let the LAN side get an IP then swapped it over to a static /59 with the Prefix ID 0 being the parent (2603:xxxx:yyy:e0:: is how my /59 looks with the Prefix ID as 0). I then defined my prefix delegation as e1 through ff (2603:xxxx:yyy:e1:: in the from field, 2603::xxxx:yyy:ff:: in the to field) as my prefix delegation range which means that anything other that e0 is an IPv6 prefix that I can delegate out as a separate /64. Confirmed IPv6 connectivity on my desktop.