#
# Debian / libvirt
#

# By default, qemu guests network interfaces are created with the
# trustGuestRxFilters attribute set to no.  This setting blocks
# neighbor solicitation and other ipv6 multicast traffic.  To enable
# neighbor solicitations, modify your interface definition in your
# guest definition XML.

# For example if you have a guest named bird0 with an interface
# definition that looks like this:

$ sudo virsh dumpxml bird0 | grep -A7 "type='direct'"
    <interface type='direct' trustGuestRxFilters='no'>
      <mac address='52:54:00:AA:BB:CC'/>
      <source dev='ens2f0np0' mode='bridge'/>
      <target dev='macvtap3'/>
      <model type='virtio'/>
      <alias name='net4'/>
      <address type='pci' domain='0x0000' bus='0x09' slot='0x00' function='0x0'/>
    </interface>

# Then use 'virsh edit bird0' change the attribute in the <interface>
# element to have the value 'yes' instead:
    <interface type='direct' trustGuestRxFilters='yes'>
      <mac address='52:54:00:AA:BB:CC'/>
      <source dev='ens2f0np0' mode='bridge'/>
      <target dev='macvtap3'/>
      <model type='virtio'/>
      <alias name='net4'/>
      <address type='pci' domain='0x0000' bus='0x09' slot='0x00' function='0x0'/>
    </interface>

# If the trustGuestRxFilters attribute is missing, it defaults to no,
# so be sure that the attribute exists and that the attribute has a
# value of 'yes'