IPv6 Android dealing with the unsupported DHCPv6



  • Hi

    I do the PPPoE (EDPNet Belgium) on Pfsense (my router is configured as PPPoE pass trough). I get a IPv6 address. I also get full score on the IPv6 test sites, but Android doesn’t support DHCPv6.
    So in my current configuration connected Androids fail to connect. They don’t fall back to IPv4.

    So now I created a separated VLAN (and separate SSID WLAN) for Android and I block IPv6 on that VLAN.
    But that doesn’t seem to be the correct way of doing this :-).

    I have the feeling I have to do something with SLAAC as this is what Android does support.
    The IPv6 coming from EDPNet is DCHPv6 and I presume it's dynamic (I’m not sure if it's not static, I only have EDPNet for 2 days).
    So I’m missing how I can convert the DHCPv6 to SLAAC so I can put the Android in the LAN/GUESTS network to simplify some things?

    Screenshots of my current attached.













  • Each LAN has its own IPv6 subnet value. So in ANDROIDS-lan you should  set the IPv6-prefix (the lan-setings page) to unique value. Zero (0) has been used for your LAN.

    On the IPv4 subject: you will be adviced to change mask /16 to /24.



  • DHCPv6 is only used on the WAN to obtain a WAN address and the prefix to use for the LAN (which it appears you're requesting a /56 prefix). Just because the WAN is using DHCPv6 to obtain its address and prefix doesn't mean a thing as far as your Android devices connecting to your LAN are concerned.

    On the LAN side, your router advertisement (RA) is set to Assisted, which allows SLAAC to function (which is what Android uses), but also allows devices to obtain a DHCPv6 address if they desire (like a PC, network printer, or other such device that you might want to have managed addresses on). The only RA setting that I'm aware of that won't allow Android devices to work is Managed. If your Android devices aren't obtaining an IPv6 address with your settings as they are, then there may be a larger issue at play here.



  • Cool thanks! Got it working by disabling the DHCPv6 server and changing the Router advertisements to unmanaged!
    The Androids also work now!

    Why should I change the internal IP's to /24? What's the advantage of it? It's just my internal network?



  • @pixeltofu:

    Cool thanks! Got it working by disabling the DHCPv6 server and changing the Router advertisements to unmanaged!
    The Androids also work now!

    Why should I change the internal IP's to /24? What's the advantage of it? It's just my internal network?

    You'll almost never need the full /16 for one network segment and even if you try to do that you'll run into serious performance problems with that many clients on the same broadcast domain. A /24 is the best compromise in a single broadcast domain for number available addresses, performance and manageability.


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