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

[Dan Williams]

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.

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.

Dan