If dhcpcd fails to get a DHCP lease, it'll down the interface -- even if
the interface has a valid IPv6 address. This is bad; the interface should be
left up and running.
fixed in dhclient-3.0.1
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on the solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.