ndp(8) on OpenBSD
The text fc3014ed2cb5, as OpenBSD 5.9 shipped it.
control/diagnose IPv6 Neighbor Discovery Protocol (NDP)
Flags it lists
-
-A -
-H -
-P -
-R -
-V -
-a -
-c -
-d -
-f -
-n -
-p -
-r -
-t