dhcpcd-discuss

Hi Timo

On 2014-08-06 19:26, Timo Rothenpieler wrote:
> I'm using dhcpcd to delegate an IPv6 prefix for my local LAN.
> It's receiving the prefix from the upstream router, which in this case
> is an AVM FritzBox with IA_PD enabled.
> Everything works great, except for one problem: The prefix is dynamic
> and changes at least once a day. Dhcpcd does not react to that, so as a
> result my LAN is unable to communicate via IPv6, as the prefix it still
> has is no longer valid.
>
> The Fritzbox seems to send some event on prefix change though, i have
> the following in my log:
>
> dhcpcd[2319]: enp2s0: unauthenticated RECONFIURE6 from fe80::....
>
> But nothing happens after that.
>
> The relevant part of my dhcpcd config is:
>
> noipv6rs
> noipv4ll
> denyinterfaces enp1s0
>
> interface enp2s0
> ia_pd 1 br0/1/64
>
>
> I'm using dhcpcd version 6.4.3

Well, the clue is in the message

> dhcpcd[2319]: enp2s0: unauthenticated RECONFIURE6 from fe80::....

And the relevant section from RFC3315

15.11. Reconfigure Message

   Servers and relay agents MUST discard any received Reconfigure
   messages.

   Clients MUST discard any Reconfigure messages that meets any of the
   following conditions:

   -  the message does not include DHCP authentication:

      *  the message does not contain an authentication option.

      *  the message does not pass the authentication validation
         performed by the client.

This is not optional, so you need to configure your Fritz! box and 
dhcpcd for authentication - any will do, even a simple token.
See dhcpcd.conf(5) for how to configure dhcpcd.

Thanks

Roy