Comment 25 for bug 1447715

I'm re-opening this for Xenial, moving from Wontfix back to in progress. This is because while 'normal' dhcpv6 works without this fix because of the patch to dhclient (see my explanation in comment 23), there is a special case of using dhclient in 'stateless' mode, i.e. dhclient -6 -S. In that mode, dhclient does not call its 'PREINIT6' which is where the wait-for-dad patch was added. When configuring ifupdown in this way, dhclient still fails due to this bug; e.g.:

auto eth0
iface eth0 inet6 auto
  dhcp 1

if eth0 is down, then running ifup eth0 with the above config will result in dhclient always failing due to this bug.