Interface index which uniquely identifies the outgoing
IPv6 interface to which this entry is applicable.
An interface identified by a particular value in this
object is the same interface as identified by the
same value of wfIpv6IfIndex.
The index value of 0 means 'match any interface',
i.e. all packets that are to be forwarded will
match this filter parameter. Note that packet which
are addressed to the router itself will not match
a filter that has zero as its wfIpv6FilterOutIfIndex
value.
The index value of -1 means that only packets which
are addressed to the router itself match this filter
parameter.
The index value of -2 means that all packets, forwarded
or addressed to the router itself, match this filter
parameter.