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Anyone using IPv6 with a /60?

Discussion in 'Tomato Firmware' started by blah123, Mar 16, 2014.

  1. blah123

    blah123 Reformed Router Member

    I'm trying to use both additional virtual wireless networks and IPv6 so I need something more than a /64. I'm on Comcast so I can get a /60 with DHCPv6 with Prefix Delegation. I'm using Toastman v1.28.7503.7 and I haven't tried any other Tomato variants. So I'm not sure if this is just an issue with Toastman builds or Tomato in general. When I set the prefix to 60 instead of 64 it doesn't seem to make the necessary changes to some of the configuration files. I was able to get the router working by making changes to the /tmp/etc/dhcp6c.conf file and restarting dhcp6c and removing an ip6tables rule.

    Here is the modified dhcp6c.conf file. I added the lines with that start with *.

    interface vlan2 {
    * send ia-na 0;
    send ia-pd 0;
    send rapid-commit;
    request domain-name-servers;
    * request domain-name;
    script "/sbin/dhcp6c-state";
    id-assoc pd 0 {
    * prefix ::/60 infinity;

    prefix-interface br0 {
    sla-id 0;
    sla-len 4;

    * prefix-interface br1 {
    * sla-id 1;
    * sla-len 4;
    * };
    id-assoc na 0 { };

    I also had to remove this ip6tables rule from the FORWARD chain. I assigned the virtual wireless network to br1 so without removing this rule the virtual wireless network couldn't get out to the wan.

    ip6tables -A FORWARD -o vlan2 ! -i br0 -j logdrop

    Has anyone else tried to do something similar to this and if so were you able to get it work just from the web GUI?
  2. misterC

    misterC Serious Server Member

    I could not get this to work. Whenever i restart dhcp6c, the file is overwritten. Am I missing a step? I tried both the config file in /tmp/etc and /etc.
  3. darkknight93

    darkknight93 Networkin' Nut Member

    Dnsmasq itself follows RFC roules and specifications - so /64 is what he expects and this address range enables autoconfig Feature. not /65 or less than /63..
    so this might be an issue caused by IPv6 Design

    you could seperate 2 /64 - using /63 of your prefix on 2 lan ports -> mapped to vlans.
    your router will be Gateway for poth subnets, Routing packets locally although Internet adresses are supplied in the packets travelling across your 2 subnets.
  4. darkknight93

    darkknight93 Networkin' Nut Member

    EDIT: I'm on shibby mod but toastman Firmware also uses dnsmasq for router adv in ipv6 right?
    so you Need to edit the advanced -> DNSmasq page i think

    for logging Details check /var/log/messages , restart the Service and check what Settings are compiled out of your config
  5. Spyros

    Spyros LI Guru Member

    My ISPs router gives a /56 delegated prefix fine but it uses radvd and dhcpv6, not dnsmasq.
  6. misterC

    misterC Serious Server Member

    Comcast currently gives a /60 instead of a /56 delegated prefix. But I have not been able to get Toastman's firmware to pull the /60.
  7. misterC

    misterC Serious Server Member

    Comcast uses prefix delegation. Since i have multiple VLAN's, I expected Toastman firmware dhcpv6 client to be able to request a /60 prefix. http://www.ietf.org/rfc/rfc3633.txt . I assumed whatever Toastman is using for a dhcpv6 client would send the hint to my ISP's DHCP server to get the /60. I thought DNSMasq's role was handling DHCP on my lan side. So dnsmasq would assign /64's to my configured vlan's out of the /60 the dhcpv6 client picked up.

    While I have used Toastman for a over a year, I never bother looking under the hood. Apologies if I am misunderstanding the role of dnsmasq.
  8. Spyros

    Spyros LI Guru Member

    Check your dhcp6c.conf in /etc, if sla-len 4; then dhcpv6 requests a /60 then dnsmasq will provide a /64 to each LAN interface (br0,br1 etc). That's how it works.
  9. misterC

    misterC Serious Server Member

    Problem I'm having is that dhcp6c.conf is being overwritten when I restart dchp6c. Have not found what is causing that. I don't see a /etc/init.d directory so not sure where else to look. Hopefully I have time this weekend to do more digging.
  10. Spyros

    Spyros LI Guru Member

    Why you want to edit dhcpc.conf? If there is no ipv6 in the second lan interface you have to add a line in advanced->dhcp/dns like

    dhcp-range=::1, ::FFFF:FFFF, constructor:br1, ra-names, 12h
    you may have to change br1 accordingly
  11. blah123

    blah123 Reformed Router Member

    misterC are you using a Toastman version or something else and which version specifically? Mine has been running just fine since I made that original post. /etc is just a link to /tmp/etc so that should have been the same file.
  12. misterC

    misterC Serious Server Member

    I'm using toastman. Have not had time to try modifying the file again.

    Tomato Firmware v1.28.7505 MIPSR2Toastman-RT K26 USB VLAN-VPN

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