dhcpcd-discuss

On Wed, Feb 3, 2016 at 4:55 AM, Roy Marples <roy@xxxxxxxxxxxx> wrote:

> On 02/02/2016 15:58, Nicholas Williams wrote:
> > Okay, so here's where I'm not following. As shown below, I can configure
> > the interface with dhcpcd, get an IPv6 address, and use it, but my
> > DHCPv6 lease info is empty:
> >
> > That's it. There's no more information in my lease. I don't
> > have dhcp6_ia_na1_ia_addr1, name_servers, domain_search, or any other of
> > the information you have in your lease in my lease. What am I missing /
> > misunderstanding?
>
> That address looks like it was configured from the result of a RS/RA
> transaction, not DHCPv6.
>
> You don't *need* DHCPv6 at all for auto configured IPv6 to work - you
> can even transmit DNS information in the RA these days.
>
> Again, you're posting dhcpcd output but stopping when it forks.
> We need to see the logs after it forks.
> In in doubt, use the --logfile /tmp/dhcpcd.log option when starting it
> and attach that file next time.


So, I understand a good deal about IPv6 and DHCPv6, but clearly I don't
understand enough. :-) I didn't properly understand that RS/RA was not
DHCPv6.

Here's my config file:

$ cat /etc/dhcpcd.conf
allowinterfaces eth2
interface eth2
option subnet_mask
option broadcast_address
option routers
option domain_name_servers
option domain_search
option domain_name
option interface_mtu
option dhcp6_name_servers
option dhcp6_domain_search
ia_na

I ran dhcpcd in IPv6 mode only to make the output less hard to filter
through:

$ sudo dhcpcd --logfile /tmp/dhcpcd.log -6 eth2

And here's the log:

$ cat /tmp/dhcpcd.log
Feb 03 12:48:11 DUID 00:01:00:01:1e:43:88:3a:08:00:27:21:d4:16
Feb 03 12:48:11 eth2: IAID 27:21:d4:16
Feb 03 12:48:11 eth2: soliciting a DHCPv6 lease
Feb 03 12:48:11 eth2: soliciting an IPv6 router
Feb 03 12:48:11 eth2: Router Advertisement from fe80::1423:8585:11f5:dfc8
Feb 03 12:48:11 eth2: adding address
2600:1004:b15b:f338:a00:27ff:fe21:d416/64
Feb 03 12:48:11 forked to background, child pid 1406
Feb 03 12:48:12 eth2: DHCPv6 REPLY: No addresses available for this
interface.
Feb 03 12:48:13 eth2: DHCPv6 REPLY: No addresses available for this
interface.
Feb 03 12:48:15 eth2: DHCPv6 REPLY: No addresses available for this
interface.
Feb 03 12:48:19 eth2: DHCPv6 REPLY: No addresses available for this
interface.

So it sounds like I'm definitely getting autoconfiguration and not DHCPv6,
which I'm guessing is why I have no lease. The problem probably stems from
the fact that I'm using a Verizon LTE connection to test this. At the time,
I wasn't able to test this on my VyOS router, and my VyOS router kept me
from having access to IPv6, so I had to use my hotspot to test IPv6
(because Verizon has global IPv6 support). Apparently Verizon doesn't do
DHCPv6, just autoconfiguration (in contrast to Comcast, which supports
either).

My apologies for wasting any of your time. :-/

Nick