Thank you Dan, for the analysis. Per comment #23, I'll mark Won't Fix
for xenial.
** Changed in: ifupdown (Ubuntu Xenial)
Status: In Progress => Won't Fix
--
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:
Won't Fix
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.
Related Bugs:
* bug 1633479: dhclient does not wait for ipv6 dad (duplicate address
detection)
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
