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    6rd Tunnel with AT&T Uverse IPv6

    Scheduled Pinned Locked Moved IPv6
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    • O
      ortizdr
      last edited by

      I am unable to get this to work in my setup. I have a 589 and have followed the directions to a t. My WAN_6RD gateway is offline and I can't ping. The only time I saw it come online was while the 589 was rebooting. But as soon as it finished booting the gateway went offline. I'm guessing that only one IP address can contact the border relay and since the 589 is always going to attempt, the 589 overrides. Oh well, fingers crossed for HE tunnels or something else to come back!

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      • C
        cmb
        last edited by

        The nature of how 6rd works, only one tunnel can exist per public IP that you have. The v6 gateway IP is never pingable on AT&T 6rd (and likely most if not all other providers).

        If you have one of the 2wire RG boxes as your modem, recent firmware versions on it block IP protocol 41 including their own 6rd. Apparently no way to work around that. That also breaks HE.net tunnels.

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        • O
          ortizdr
          last edited by

          So it turns out it was working the whole time, just like stated above the Gateway does not respond to pings. Now i just need to figure out DHCPv6 and how to come up with a range and then all will be good!

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          • A
            azzido
            last edited by

            When I was testing AT&T IPv6 I discovered that if 6rd tunnel is terminated on pfSense IPv6 download speed can be considerably lower than IPv4 download speed:

            
            IPv4    IPv4        IPv4        IPv6    IPv6        IPv6
            ms      Down Mbps   Up Mbps     ms      Down Mbps   Up Mbps
            22      50.00       5.58        21      20.42       5.26        Chicago Server
            53      32.14       5.46        55      20.07       5.35        Denver Server
            48      39.20       5.46        62      17.67       5.40        Boston Server
            
            

            If 6rd is terminated on NVG589 and IPv6 on pfSense WAN is set to DHCP, then IP v6 and v4 speeds are comparable:

            
            IPv4    IPv4        IPv4        IPv6    IPv6        IPv6
            ms      Down Mbps   Up Mbps     ms      Down Mbps   Up Mbps
            21      50.27       5.63        20      48.77       5.64        Chicago server
            53      42.56       5.58        58      48.25       5.44        Denver server
            48      46.08       5.64        61      47.59       5.42        Boston server
            
            

            Testing was being done using http://speedtest.comcast.net

            This is a known issue and does not have anything to do with pfSense. You can read more about it here http://www.dslreports.com/forum/r29436224-UVERSE-IPv6-Problems. It is not clear if the issue lies with NVG589 or 6rd endpoints.

            icemanncsu, since you are one of those unique people that are using AT&T without NVG589, could you run Comcast speed test and report if you are seeing speed difference between IPv6 and IPv4.

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            • O
              ortizdr
              last edited by

              6rd tunnels (he.net) now work with att. They are no longer blocking protocol 41.

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              • C
                CynicalFrost
                last edited by

                I'm having some strange IPv6 connectivity issues with my setup where connections to random IPv6 enabled sites are flaky and take forever to load (if they do before I stop loading the page after like 3 minutes).

                Setup:
                I have a Motorola NVG589 set in "bridge" mode and have pfSense handling the 6rd tunneling where my settings for the WAN port are

                6rd prefix: 2602:300::/28
                6rd Border Relay:12.83.49.81
                6rd IPv4 Prefix length: 0 bits

                I've also configured several LAN ports to track the WAN interface, assigning each a Prefix ID from 0 to 5.

                I suspected that it might be a MTU issue, but after trying various combinations and test cases, I'm not so sure anymore.

                Is anyone else having similar issues?

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                • O
                  ortizdr
                  last edited by

                  I had an HE tunnel up and running but i still experienced an MTU issue. Something is messed up somewhere.

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                  • demD
                    dem
                    last edited by

                    @CynicalFrost:

                    I suspected that it might be a MTU issue, but after trying various combinations and test cases, I'm not so sure anymore.

                    I see similar issues unless I force router advertisements to send 1280 for the MTU (edit /var/etc/radvd.conf and change AdvLinkMTU to 1280, then send a SIGHUP to radvd).

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                    • A
                      azzido
                      last edited by

                      CynicalFrost, i had similar issues and most of them were caused by MTU size being too large. Your best bet is to change MTU on your PC to 1472 and see if the issue persists.

                      The whole MTU thing is a bit convoluted. If you change radvd config file directly, it will revert back to the interface MTU size on pfSense if something changes on the firewall and config file is regenerated. Your only reliable option here is to patch PHP code that generates radvd config file.

                      If you change MTU size on the pfSense interface, but leave MTU on your client unchanged you will run into problems with IPv4 traffic that comes in with do not fragment flag set. One thing to keep in mind is that Linux and Windows has separate MTU settings for IPv4 and IPv6 and you can set them independently, but FreeBSD (as far as I know) only has one setting that applies to both IPv4 and IPv6. If you reduce MTU size on pfSense interface you also need to reduce IPv4 MTU size on client machines manually, because RA advertisements only affect IPv6 MTU size.

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                      • C
                        CynicalFrost
                        last edited by

                        @ortizdr:

                        I had an HE tunnel up and running but i still experienced an MTU issue. Something is messed up somewhere.

                        Funny enough, when I setup an HE tunnel, it works without issue without having to adjust the MTU.

                        @azzido:

                        CynicalFrost, i had similar issues and most of them were caused by MTU size being too large. Your best bet is to change MTU on your PC to 1472 and see if the issue persists.

                        The whole MTU thing is a bit convoluted. If you change radvd config file directly, it will revert back to the interface MTU size on pfSense if something changes on the firewall and config file is regenerated. Your only reliable option here is to patch PHP code that generates radvd config file.

                        If you change MTU size on the pfSense interface, but leave MTU on your client unchanged you will run into problems with IPv4 traffic that comes in with do not fragment flag set. One thing to keep in mind is that Linux and Windows has separate MTU settings for IPv4 and IPv6 and you can set them independently, but FreeBSD (as far as I know) only has one setting that applies to both IPv4 and IPv6. If you reduce MTU size on pfSense interface you also need to reduce IPv4 MTU size on client machines manually, because RA advertisements only affect IPv6 MTU size.

                        I've done some variation of this recommendation.  I've changed the MTU value within pfSense to 1450 for my LAN port (leaving the MTU for WAN port at 1500) and then disabled/re-enabled my ethernet adapter in Windows so that the MTU values gets reset properly.  I've double checked the MTU values in windows after disabling/re-enabling and both IPv4 and IPv6 have values set to 1450 (which should be more than enough).  I still wind up with connection issues.

                        I'd rather not rely on setting the MTU value on my PC since I have other devices (tablet, phone) that don't give me that option.

                        I'm tempted to just forget the 6rd and just use HE, but I feel like that's inefficient

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                        • A
                          azzido
                          last edited by

                          Never heard of IPv4 MTU adjusting itself automatically. Use below commands to check MTU size on Windows.

                          
                          netsh interface ipv4 show interfaces       Show IPv4 MTU
                          netsh interface ipv6 show interfaces       Show IPv6 MTU
                          
                          

                          If you use Firefox you can easily disable IPv6 by going to 'about:config' and setting 'network.dns.disableIPv6' to true. So whenever you are having issues quickly disable IPv6 and see if the issue goes away. You can also install IPvFox add-on that will tell you what IPs each website is accessing.

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                          • C
                            CynicalFrost
                            last edited by

                            I take back the MTU for IPv4 adjusting. I thought it had when I ran those commands the last time I tested things out.

                            anyway, results as requested:

                            PS C:\Users\alex> netsh interface ipv4 show subinterface

                            MTU  MediaSenseState  Bytes In  Bytes Out  Interface
                            –----  ---------------  ---------  ---------  -------------
                              1500                1    611662    1532564  Ethernet
                              1500                5          0          0  Wi-Fi
                            4294967295                1          0      29698  Loopback Pseudo-Interface 1
                              1500                5          0          0  Local Area Connection* 1

                            PS C:\Users\alex> netsh interface ipv6 show subinterface

                            MTU  MediaSenseState  Bytes In  Bytes Out  Interface
                            ------  ---------------  ---------  ---------  -------------
                              1450                1    769901    125344  Ethernet
                              1500                5          0        298  Wi-Fi
                              1280                5          0          0  isatap.mydomain.com
                            4294967295                1          0      24172  Loopback Pseudo-Interface 1
                              1500                5          0        225  Local Area Connection* 1
                              1280                1        912      2191  Local Area Connection* 4

                            Note: Using ethernet at the time I checked the MTU.  Wifi was turned off.

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                            • A
                              azzido
                              last edited by

                              I did forget to mention one thing. Even if you change MTU on your PC, whenever new RA message arrives that advertises MTU size, Windows will update IPv6 MTU.

                              Thus to properly test if the MTU size is causing issues you need to change MTU on pfSense LAN interface, which will force radvd to advertise new MTU and Windows to update IPv6 MTU size and change MTU on Windows interface which will change IPv4 MTU.

                              This is one of the reasons why I ditched AT&T IPv6 at home.

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                              • C
                                CynicalFrost
                                last edited by

                                @azzido:

                                I did forget to mention one thing. Even if you change MTU on your PC, whenever new RA message arrives that advertises MTU size, Windows will update IPv6 MTU.

                                Thus to properly test if the MTU size is causing issues you need to change MTU on pfSense LAN interface, which will force radvd to advertise new MTU and Windows to update IPv6 MTU size and change MTU on Windows interface which will change IPv4 MTU.

                                This is one of the reasons why I ditched AT&T IPv6 at home.

                                Right. I realized this when I was testing earlier and found that my IPv6 MTU kept getting reset to a higher value when I set the MTU locally until I set it for the LAN interface.

                                So far, I'm not having much luck with reliable IPv6 connectivity and may just ditch trying to use the 6rd tunnel.  I did test out using a HE tunnel and that did seem more reliable so I might go with that.

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                                • M
                                  martylavender
                                  last edited by

                                  I know there has been no traffic on this post for quite a while but I was intrigued by this post.

                                  I have Uverse Gigapower and am currently using the NVG599 RG for Internet. Is it in fact possible to dump the gateway and connect my pfSense box up and have it masquerade as the RG?

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                                  • O
                                    ortizdr
                                    last edited by

                                    @martylavender:

                                    I know there has been no traffic on this post for quite a while but I was intrigued by this post.

                                    I have Uverse Gigapower and am currently using the NVG599 RG for Internet. Is it in fact possible to dump the gateway and connect my pfSense box up and have it masquerade as the RG?

                                    This has in fact been discussed multiple times over at DSLreports.com
                                    https://www.dslreports.com/forum/r29903721-AT-T-Residential-Gateway-Bypass-True-bridge-mode

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                                    • M
                                      martylavender
                                      last edited by

                                      LOL I was actually just reading through that same post. Seems pretty interesting. I have the old version of the Netgear switch theyre talking about. It has since died. Wonder if I can RMA it! :P Otherwise, I need to pick up a new switch anyway.

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