Uverse IPV6



  • ATT just released some new firmware for the NVG599 modem which seems to change the way IPV6 works.  Previously I was using the 6rd setup commonly found in the forums.

    Now, my IPV6 setup required using DHCP6 for WAN.  All other options are left at default.  This allows the WAN to get an IPV6 address and I can ping ipv6.google.com from diagnostic tab using source of the WAN using IPV6 protocol.  So, I'm most of the way there.  Here is the issue:

    LAN is set to Track Interface for IPV6, with Prefix ID of 0, but the interface never obtains an IPV6 address, and none of the LAN clients are able to obtain a IPV6 address.

    Any ideas on how to get the LAN pfSense interface and LAN clients to pull an IPV6 address?



  • Need more input. Can you have a look at the dchp logs and look for dhcp6c.

    BTW, what pfsense version are you running. Pre 2.4 versions had some strange behaviour with ipv6 dhcp, resolved in 2.4.



  • Sure, I can provide whatever is needed, but at this point I’m just shooting in the dark.

    Logs with “dhcp6c” as filter repeat this over and over:

    Time Process PID Message
    Oct 13 05:46:56 dhcp6c 24850 Sending Solicit
    Oct 13 05:46:56 dhcp6c 15066 unexpected interface (3)

    Also, it’s worth noting that I have a dual WAN setup and have a working DHCP6 setup for WAN1 which provides IPV6 to LAN1.  This is from Comcast.

    My objective is to have IPV6 on WAN2, from ATT, and provide LAN2 with IPV6.

    LAN1 and LAN2 are physically separate interfaces and are not VLANs.

    Also worth noting is this was working with a 6rd config until a modem firmware change caused issues with that setup.  Basically with 6rd config, there was massive delay and dramatic speed loss. The only way to fix it was to disable 6rd and use DHCP6. With the DHCP6 config, my WAN2 obtains an IPV6 address, but the LAN2 will not pull one.



  • You cannot have dhcp6 on two interfaces… sorry about that.



  • I have seen some forum posts and bugs about this.  Is that true even if it’s two different physical interfaces, two different ISPs and two different subnets?

    Is 6rd the only way to get to this work then?  If so, any ideas why using that configuration would cause significant latency?

    This is the setup that I had used previously:

    https://forum.pfsense.org/index.php?topic=93625.0



  • I wonder if turning off the modems LAN side ipv6 would help?  Thoughts?




  • This is a link to someone with exact same problem as me.

    https://www.dslreports.com/forum/r31444835-NVG599-Updated-Overnight-IPv6-tunnel-no-longer-can-be-used

    Looks like he ended up downgrading his firmware.

    Appears that ATT is making some changes to the way IPV6 works.



  • @mloiterman:

    I have seen some forum posts and bugs about this.  Is that true even if it’s two different physical interfaces, two different ISPs and two different subnets?

    Is 6rd the only way to get to this work then?  If so, any ideas why using that configuration would cause significant latency?

    This is the setup that I had used previously:

    https://forum.pfsense.org/index.php?topic=93625.0

    You could always use an IPv6 tunnel broker on one of the ISP's, or you need an ISP that will give you a static IPv6 allocation, that's the way I would do it. One dhcp and one static.

    The problem is with the way the config file is written for dhcp6c and the way it is launched. At present the config file does not handle dual interfaces, if my memory serves me correctly, and I have looked at this, it would write two config files, one for each interface and then attempt to launch dhcp6c twice! After I did a lot of work on dhcp6c and the areas in pfSense where it's handled I decided that life was too short to start trying to sort that out as well.  8)



  • Thanks for the help.  I've disabled IPV6 on the second WAN and things are running smoothly now.  ATT has some work to do on their side and pfSense doesn't support two DHCP6, so there is no point trying to wrestle with it.