[Bug 1218959] [NEW] KVM virbr# no longer forwards multicast traffic by default (U12.04)

[Michael Cook]

Public bug reported:

A recent kernel update (Apr 2013) has made it's way to U12.04.2 LTS
(approx June-Aug 2013) and has stopped the (default) behaviour of
automatically forwarding multicast traffic over virbr#.  Some updates
the bridge subsystem now, by default, disable multicast traffic without
IGMP Querier being enabled on that bridge.

The corresponding Fedora/RHEL bug tracks the progress/updates of this specific change in relation to Fedora.  
https://bugzilla.redhat.com/show_bug.cgi?id=880035

(I have yet to find a similar bug report in Ubuntu so I have created
this bug to help the Ubuntu community identify multicast issues that may
arise since April 2013 in U12.04 LTS and presumably other Ubuntu
releases as backports are made and break regression testing.)

Using the latest patches in U12.04.2 LTS this following addition, with some modifications, can be made to the udev rules will enable multicast on virbr# bridge:
https://bugzilla.redhat.com/show_bug.cgi?id=880035#c38

While this is an improvement/correction to KVM bridge networking it has
broken existing functionality in U12.04.2 LTS and broke regressed
functionality that once worked.

** Affects: bridge-utils (Ubuntu)
     Importance: Undecided
         Status: New

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to bridge-utils in Ubuntu.
https://bugs.launchpad.net/bugs/1218959

Title:
  KVM virbr# no longer forwards multicast traffic by default (U12.04)

Status in “bridge-utils” package in Ubuntu:
  New

Bug description:
  A recent kernel update (Apr 2013) has made it's way to U12.04.2 LTS
  (approx June-Aug 2013) and has stopped the (default) behaviour of
  automatically forwarding multicast traffic over virbr#.  Some updates
  the bridge subsystem now, by default, disable multicast traffic
  without IGMP Querier being enabled on that bridge.

  The corresponding Fedora/RHEL bug tracks the progress/updates of this specific change in relation to Fedora.  
  https://bugzilla.redhat.com/show_bug.cgi?id=880035

  (I have yet to find a similar bug report in Ubuntu so I have created
  this bug to help the Ubuntu community identify multicast issues that
  may arise since April 2013 in U12.04 LTS and presumably other Ubuntu
  releases as backports are made and break regression testing.)

  Using the latest patches in U12.04.2 LTS this following addition, with some modifications, can be made to the udev rules will enable multicast on virbr# bridge:
  https://bugzilla.redhat.com/show_bug.cgi?id=880035#c38

  While this is an improvement/correction to KVM bridge networking it
  has broken existing functionality in U12.04.2 LTS and broke regressed
  functionality that once worked.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/bridge-utils/+bug/1218959/+subscriptions