Does TomatoUSB support DHCPv6-PD?

Discussion in 'Tomato Firmware' started by Morac, Jun 8, 2012.

  1. Morac

    Morac Network Guru Member

    I'm running the latest toastman build of TomatoUSB and while it looks like it support DHCPv6 on the WAN side for IPv6 support, I don't see anything about DHCP-PD which is required to allow serving IPv6 ip addresses from your ISP.

    For example Comcast gives customers using a router a /64 block of publicly IPv6 addresses. When a client behind the router requests an address via DHCP, the router should forward it on the the DHCPv6 server and then forward the response back to the client.

    It looks like OpenWRT supports it. Does Tomato support it?

  2. rgolds

    rgolds Serious Server Member

    I'm in the same situation as you; I have Comcast and use the latest Toastman Tomato build.

    The only way I've been able to get IPv6 working so far is through a 6to4 Anycast Relay, though that isn't true native IPv6 - not ideal. See my post here for details (and hopefully, a solution for native IPv6 support will appear in that thread at some point).

    If you do figure it out, I'd appreciate if you can post that here; I'll do likewise.

  3. LanceMoreland

    LanceMoreland Network Guru Member

    Has anyone figured out how to make this work with Comcast? I had a tunnel running fine for a while but can't make tomato work on Comcast's native IPv6.

    Edit: checking around on the internet it is pretty clear that Tomato's DHCPv6 is broken. There are no reports of anyone getting it to work with Comcast.
  4. Morac

    Morac Network Guru Member

    I was told IPv6 isn't available on my headend yet. I don't know if that's true or not, but it would explain why I can't even pull an IPv6 address via DHCP.

    In the mean time I dumped my /etc/dhcpv6.conf file:

    I found the documentation for this at but I can't figure out what it really means. If I'm interpreting it correctly, the sla-id and sla-len values may need to be changed or not (I have no idea).

    From what I've read, it's actually up to the router to assign IPv6 addresses that are within the range of the IP range assigned by Comcast. Comcast is assigned /64 block addresses which if I under stand correctly means the prefix will be 64 bits. So Comcast will give a DHCPv6 prefix designation address of AAAA:BBBB:CCCC:DDD: and the user will "own" all IPV6 addresses in that subnet (from AAAA:BBBB:CCCC:DDDD:0:0:0:0 to AAAA:BBBB:CCCC:DDDD:FFFF:FFFF:FFFF:FFFF excluding illegal addresses). It's the router's job when getting a local DHCPv6 request to assign IPv6 addresses in that subnet by combining the prefix (AAAA:BBBB:CCCC:DDDD) with a locally unique address (VVVV:XXXX:YYYY:ZZZZ) such that the actual IPv6 given to a local device looks likes AAAA:BBBB:CCCC:DDDD:VVVV:XXXX:YYYY:ZZZZ as opposed to a locally generated private IPv6 address.

    So the router doesn't actually ask the DHCPv6 server for ipv6 addresses for LAN devices, it builds them itself. That's if I'm understanding things correctly, which I may not be.

    Based on my understanding that mean setting Tomato to DHCP-PD should "just work". Being able to log things would be useful though.
  5. LanceMoreland

    LanceMoreland Network Guru Member

  6. Morac

    Morac Network Guru Member

  7. Toastman

    Toastman Super Moderator Staff Member Member

    Wait a little, guys, there seems to be a lot of difference in opinion over the best way to settle this, it's being discussed at the moment.
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