touch-packages team mailing list archive

[Eloy Paris <1447715@xxxxxxxxxxxxxxxxxx>]

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.

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