dhcpcd-discuss

On Mon, 2018-09-24 at 12:17 +0100, Roy Marples wrote:
> Wow.
Hi Roy,
> This is an edge case I'm not entirely sure I want to work around.

My goal is quite basic. I want choose an address in the IPv6 range that my
provider gives me.
To give a little context, the provider in question gives a /56 per server. To
obtain the IP, according to its documentation[1], I have to make a prefix
request based on a given DUID. 

When I request an address, without a prefix (via ia_na), I only have one IPv6
address (prefix + ::1). I cannot get others IP, I tried several ia_na or to
indicate an IP (via ia_na / address). Temporary prefix didn't work either.

So far, the cleanest option, seems to ask the prefix and to choose myself the
static address inside.
> Firstly, you are delegating to the same interface you're requesting on and
> dhcpcd correctly warns that your DHCPv6 server does not support this
> (OPTION_PD_EXCLUDE is missing from it's reply).If it did, then dhcpcd would
> assign an IPv6 address to the interface and it would fork to the background
> correctly.

Yes, the delegation is for the same interface I'm requesting on. Note there is
one physical interface on the server, so there is no much options.
I don't get what's wrong with this, and why PD_EXCLUDE should be used here.If I
understand correctly, the PD_EXCLUDE make sense when the delegating router
needs to use a sub prefix inside the delegated prefix (which is forbidden by
RFC 3633). In our case, the ipv6 prefix between the delegating router (provider
equipment) and the requesting router (my server) is done via link-local
addresses. So, the deletaged prefix is not used by the delegating router, and
so we don't need exclusion (PD_EXCLUDE) extension.
Side note, I made some test this afternoon with dhclient and it worked, no
PD_EXCLUDE warning and the prefix was correctly delegated.
> Secondly, if you ran dhcpcd in master mode (ie not specify an interface on
> the command line or pass the -M flag) it would also fork to the background
> correctly.
Is dhcpcd, in this mode,will continue to renew/rebind the prefix? As it didn't
take the prefix as a valid address for going to background.
Regards,
[1] https://documentation.online.net/en/dedicated-server/network/ipv6/prefix

Sébastien "Seblu" Luttringer

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