[systemd-devel] systemd-networkd fails to get DHCPv4 lease with disabled IPv6

[Tom Gundersen]

On Mon, Jul 14, 2014 at 10:38 PM, Dan Williams <dcbw at redhat.com> wrote:
> On Mon, 2014-07-14 at 11:06 -0700, David Timothy Strauss wrote:
>> On Sun, Jul 6, 2014 at 3:32 PM, Tom Gundersen <teg at jklm.no> wrote:
>> > "yes" is a synonym for "both" and "no" for "none".
>>
>> These are odd semantics, given that IPv6 is completely configurable
>> using router advertisements for even DNS information (that is, no DHCP
>> whatsoever). Perhaps the option should be Autoconfig= with options for
>> DHCPv4, DHCPv6, and RA and "yes" meaning all?
>
> Except that systemd-networkd doesn't do anything with RA at all, other
> than soliciting an RA to see if DHCPv6 is requested by the router.  The
> kernel handles all the RA processing, address assignment, and route
> assignment.  So having an Autoconfig option for "RA" wouldn't make any
> sense unless systemd somehow grew the capability to turn off kernel RA
> handling.

Yeah, at the moment we don't have the support, but eventually we
expect to handle RA in userspace too.

> But that brings up another question; I don't think systemd-networkd is
> currently capable of ensuring a machine is completely configured when RA
> is enabled, because it doesn't handle RDNSS and DNSSD options from the
> RA response.  The kernel can't handle those, because those require
> writing to /etc/resolv.conf (or a caching nameserver), which the kernel
> obviously doesn't do.  But neither does systemd-networkd.

As Lennart mentioned, this is just a matter of hooking things up.

Cheers,

Tom