A quick update -- This seems to be a timing issue, i.e. dhclient trying
to bind to the DHCPv6 port (UDP 546) on a link-local address when the
interface is not ready, but I am not sure. What I do know is that the
following patch to isc-dhcp-client 4.3.1 works around the problem:
--- a/common/socket.c
+++ b/common/socket.c
@@ -170,6 +170,11 @@
if ((info->flags & INTERFACE_STREAMS) == INTERFACE_UPSTREAM) {
*do_multicast = 0;
}
+
+ /*
+ * Wait a little before calling bind(). See LP #1447715.
+ */
+ sleep(5);
break;
#endif /* DHCPv6 */
With this patch dhclient -6 waits 5 seconds before attempting to bind(),
and that allows me to obtain an IPv6 address from the DHCPv6 server.
A machine running ArchLinux and network-manager 1.0 does not have this
problem of dhclient quitting after failing to bind(). Ubuntu 15.04 uses
network-manager 0.9.10.0 so this might be a problem with Network Manager
after all. We will have to wait and see until Ubuntu has Network Manager
1.0. In the meantime, I am all see with the above "workaround".
Cheers,
Eloy Paris.-
--
You received this bug notification because you are a member of Ubuntu
Touch seeded packages, which is subscribed to isc-dhcp in Ubuntu.
https://bugs.launchpad.net/bugs/1447715
Title:
dhclient -6: Can't bind to dhcp address: Cannot assign requested
address
Status in isc-dhcp package in Ubuntu:
New
Bug description:
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/isc-dhcp/+bug/1447715/+subscriptions
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