update for this: this patch is already included upstream in debian, and is already included in yakkety. It's not yet in xenial. It's not required in trusty (bug doesn't exist there).
additionally, bug 1633479 (which fixes this by putting the DAD wait in isc-dhcp-client) is in proposed for p/t/x/y. The root problem can be fixed in either place (ifupdown via this bug, or isc-dhcp-client via that bug), and doesn't need to be fixed in both. So SRUing this to xenial will match the code that's upstream, and will fix the bug for systems that don't have an updated isc-dhcp-client (though I don't know why anyone would update ifupdown but not isc-dhcp- client). But, once bug 1633479 is moved from proposed to released in xenial, this SRU isn't technically necessary, other than to keep code/behavior similar between xenial and y+ ifupdown. -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to ifupdown in Ubuntu. https://bugs.launchpad.net/bugs/1447715 Title: dhclient -6: Can't bind to dhcp address: Cannot assign requested address Status in ifupdown package in Ubuntu: Fix Released Status in ifupdown source package in Xenial: In Progress Status in ifupdown package in Debian: Fix Released Bug description: [Impact] When using dhcpv6 configured via ifupdown, the interface's dhcp client fails to start at boot with the error: Can't bind to dhcp address: Cannot assign requested address This is because ifupdown doesn't wait, after bringing the interface up, for it to complete its link-local Duplicate Address Detection (DAD), and the dhcp client can't bind to the link-local address because it's still in "tentative" state (until DAD completes). This is fixed upstream in debian ifupdown in version 0.8.11 by adding '-tentative' to the /lib/ifupdown/wait-for-ll6.sh script; before the script was only waiting for the link-local address to appear, now it waits until the link-local address appears and is not in 'tentative' state. [Test Case] Configure an interface, using ifupdown, with dhcpv6 (e.g. iface eth0 inet6 dhcp) and reboot. It will fail to get a dhcp address during boot. [Regression Potential] None [Other Info] After upgrading to Ubuntu 15.04 my computer is unable to obtain an IPv6 address via DHCPv6. The root cause is that dhclient is exiting with the following message: ----------------------------------------------------- Can't bind to dhcp address: Cannot assign requested address Please make sure there is no other dhcp server running and that there's no entry for dhcp or bootp in /etc/inetd.conf. Also make sure you are not running HP JetAdmin software, which includes a bootp server. If you think you have received this message due to a bug rather than a configuration issue please read the section on submitting bugs on either our web page at www.isc.org or in the README file before submitting a bug. These pages explain the proper process and the information we find helpful for debugging.. exiting. ----------------------------------------------------- The problem seems to exist in isc-dhcp-client 4.3.1-5ubuntu2 (15.04 version) because downgrading to isc-dhcp-client 4.2.4-7ubuntu14 (14.10 version) allows me to obtain an address. NetworkManager is the one launching dhclient. The two invocations (one for IPv4 and one for IPv6) are: dhclient_start(): running: /sbin/dhclient -d -q -sf /usr/lib/NetworkManager/nm-dhcp-helper -pf /run/sendsigs.omit.d /network-manager.dhclient-eth0.pid -lf /var/lib/NetworkManager /dhclient-c0a3dfde-5c0b-4cef-9c3b-563cfb1fb9d2-eth0.lease -cf /var/lib/NetworkManager/dhclient-eth0.conf eth0 dhclient_start(): running: /sbin/dhclient -d -q -6 -N -sf /usr/lib/NetworkManager/nm-dhcp-helper -pf /run/sendsigs.omit.d /network-manager.dhclient6-eth0.pid -lf /var/lib/NetworkManager/dhclient6-c0a3dfde-5c0b-4cef-9c3b- 563cfb1fb9d2-eth0.lease -cf /var/lib/NetworkManager/dhclient6-eth0.conf eth0 I do not see anything suspicious with the way both dhclients are invoked. Given that a downgrade allows me to obtain an IPv6 address I think this might be a bug in the ISC DHCP client rather than in NetworkManager. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ifupdown/+bug/1447715/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
