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    Unable to get DHCPv6 to work

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    • Z
      zingbats
      last edited by

      I've been unable to get IPv6 via DHCPv6 to work on my UK vodafone PPPoE service, but it does work with the ISP provided router. As such, I have port mirrored and packet sniffed between the working router, and the pfSense router. I'm not technical enough to analyse these DHCPv6 packets and spot what pfSense configuration I might need. I have attached the wireshark logs below in case someone is able to look into this.
      I apologise if there any any sensitive IPv6 details within it! Many thanks.

      WireShark.zip

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      • P
        pst @zingbats
        last edited by pst

        @zingbats One difference I can see is that pfSense does not include IPv6 Prefix Delegation in the request. Try changing the Interfaces / WAN / DHCP6 Client Configuration to
        8858f70d-07ce-473e-a481-4f944626adda-image.png

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        • Z
          zingbats @pst
          last edited by

          @pst thanks for this. I had already tried it, but I've made some new logs. The shorter file name is just with your tickbox suggested as above, the second is with the additional tickbox of "Only request an IPv6 prefix, do not request an IPv6 address" ticked too, as some other users in these forums have had success with this with their ISP.

          Is it worth spoofing the ISP WAN mac address?WireShark.zip

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            pst @zingbats
            last edited by

            @zingbats Odd, neither of the new logs contains the Prefix Delegation element in the request. I wonder if the interface needs a restart before the configuration is applied? Try restart the WAN in Status / Interfaces and check if that makes a difference.

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            • Z
              zingbats @pst
              last edited by zingbats

              @pst I did a full reboot with just the prefix hint box. Log attached.

              I am also going to back up and do a factory reset to see if that works.
              EDIT: Factory reset did nothing.

              pfsense prefix hint after reboot.pcapng

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              • P
                pst @zingbats
                last edited by

                @zingbats nope, still the same.

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                • Z
                  zingbats @pst
                  last edited by

                  @pst Well the factory reset didn't help either. Any other ideas?

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                  • P
                    pst @zingbats
                    last edited by pst

                    @zingbats As you suggested, you could try the MAC spoofing. If that fixes the VF rejection, great but it still doesn't explain why pfSense doesn't include the Prefix Delegation hint when it has been configured to do so. Which version of pfSense are you running?

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                    • Z
                      zingbats @pst
                      last edited by

                      @pst when I did the factory reset I spoofed the mac in the wizard and it changed nothing.

                      Running latest pfSense CE (2.7.2), x86

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                        pst @zingbats
                        last edited by

                        This post is deleted!
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                        • P
                          pst @zingbats
                          last edited by

                          @zingbats I'm out of ides for the moment. I need to pop out for a few hour, hopefully I have some new ideas when I get back.

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                            pst @zingbats
                            last edited by pst

                            @zingbats I am trying to understand how VF is configuring the IPv6 connection, postings on the net suggests they are in the process of rolling out native IPv6 support. Could you post the result of https://ipv6-test.com/ using the ISP router? It should indicate if you have native IPv6, or 6to4 (see https://forum.vodafone.co.uk/t5/Other-broadband-queries/ipv6-settings/td-p/2742474/page/2)

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                            • Z
                              zingbats @pst
                              last edited by

                              @pst I had already read up on the 6to4, but as I'm a new customer, I knew I'd be on the native. Here's the screenshot from the vodafone router

                              Vodafone ipv6.png

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                              • P
                                pst @zingbats
                                last edited by

                                @zingbats good you've native, pity as it closes another avenue. With everything you've already tested it doesn't really leave much else to try. I still suspect VF is rejecting the DHCPv6 Request because pfSense is not sending the same parameters as the original router.

                                Here's what pfSense is sending

                                c4e7587d-6dd1-4d84-aa29-dff393df9127-image.png

                                Whereas the VF router sends additional information:

                                597183f2-4db4-4205-8c2d-5309169b6c61-image.png
                                2368d8cd-1153-4431-b384-147e6d160291-image.png

                                You could try adding the missing parameters (Option Request rDNS, Reconfigure Accept, Domain Name, and Prefix Delegation (which should have been included when setting Send Hint)) by enabling WAN / DHCP6 Client Configuration / Advanced Configuration, and then populate Advanced DHCP6 Client Configuration. I have never attemped this, and would not have much to contribute. There might be someone else though, that can provide the final pieces of this puzzle.

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                                • Z
                                  zingbats @pst
                                  last edited by

                                  @pst I tried the advance options, but it seems like the manual that pfSense references does not support these DHCP6 options.

                                  https://man.freebsd.org/cgi/man.cgi?query=dhcp6c.conf&apropos=0&sektion=0&manpath=FreeBSD+10.3-RELEASE+and+Ports&arch=default&format=html

                                  I imagine that means it's game over sadly.

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                                  • P
                                    pst @zingbats
                                    last edited by

                                    @zingbats said in Unable to get DHCPv6 to work:

                                    I imagine that means it's game over sadly.

                                    Not yet, it might just be a little more complicated than first imagined :)

                                    Let's try and add one parameter:

                                    e94d63c7-c781-472e-b8e0-80525ac3f4cd-image.png

                                    I think this falls under the manual section

                                    b39f786d-7899-4cb7-9fa8-9368c9b94564-image.png

                                    In pfSense that would I guess translate into

                                    b1e497bb-368b-42ba-a5df-4eb101c4384a-image.png

                                    If that works we should see pfSense sending this parameter to the DHCP6 Request, and we can continue with the next parameter.

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                                    • Z
                                      zingbats @pst
                                      last edited by

                                      @pst I have tried setting JUST this as requested, and replicating the complete default config file (which includes domain-name-servers) and I don't see any options passed in the packets.

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                                        pst @zingbats
                                        last edited by

                                        @zingbats I wonder if there's a bug in the 2.7.2 version of pfSense then. I did a test on my 23.09.1, adding sip-server-list as advanced configuration. I noticed that ONLY sip-server-list was requested, not DNS servers and other stuff which is usually asked for. The DHCPv6 Request was rejected and no IPv6 connectivity established. That seems to indicate that the Advanced DHCP6 configuration needs to be a complete configuration, AND that the DHCPv6 server might reject a Request that does not include everything it is expecting.

                                        That both the Advanced DHCP6 configuration and "Send IPv6 prefix hint" seems to be ignored by pfSense 2.7.2, suggests a bug IMHO.

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                                        • Z
                                          zingbats @pst
                                          last edited by

                                          @pst luckily I'm in my 14 day cancellation window with my ISP so I'm moving to BT who seem to better support IPv6 without the need for non-standard options. Hopefully IPv6 will become more stable and configurable in pfsense soon, as it seems the dhcp6c is missing modern request options such as those required by vodafone.

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                                          • P
                                            pst @zingbats
                                            last edited by

                                            @zingbats said in Unable to get DHCPv6 to work:

                                            request options such as those required by vodafone

                                            or it could just be us not understanding what is needed...

                                            BTW, have you tried configuring SLAAC instead of DHCP6 on the WAN? (the last straw)

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