I'm using dnsmasq to assign IPs to machines. It can also send router advertisement messages allowing to use SLAAC in VMs to get IPv6 addresses.
I'm an IPv6 novice so my description could not be completely accurate, but these advertisement messages MUST be sent using link local IPv6 addresses to be conformant, otherwise OSes ignore them.
In FreebSD bridge(4) interfaces by default have no link local addresses.
Adding the auto_linklocal causes the interface to autoassign a valid link local address, so SLAAC works properly.
I suggest enabling this unconditionally, I don't see any ill effects this could cause, considering the bridge is used as a swtich.
I'm using dnsmasq to assign IPs to machines. It can also send router advertisement messages allowing to use SLAAC in VMs to get IPv6 addresses.
I'm an IPv6 novice so my description could not be completely accurate, but these advertisement messages MUST be sent using link local IPv6 addresses to be conformant, otherwise OSes ignore them.
In FreebSD bridge(4) interfaces by default have no link local addresses.
Adding the auto_linklocal causes the interface to autoassign a valid link local address, so SLAAC works properly.
I suggest enabling this unconditionally, I don't see any ill effects this could cause, considering the bridge is used as a swtich.