This type is used by OpenVZ venet interfaces. We "handle" such an
address type just by blanking the MAC address field.
Lack of support for this type of interface was preventing Nmap from
working on certain systems.
http://seclists.org/nmap-dev/2012/q2/763
An earlier message about this same type of interface is
http://seclists.org/nmap-dev/2009/q3/303