static: Immediately answer any Neighbor Solicitation Messages (if they match the IP rule). iface: Forward the Neighbor Solicitation Message through the specified interface and only respond if a matching Neighbor Advertisement Message is received. auto: Same as iface, but instead of manually specifying the outgoing interface, check for a matching route in /proc/net/ipv6_route.
Declarations
Type
one of "static", "iface", "auto"Default
"auto"