diff --git a/usr.sbin/pim6sd/mtrace6/mtrace6.8 b/usr.sbin/pim6sd/mtrace6/mtrace6.8
index 75f2d8cdbcd0..ff40022b4dcb 100644
--- a/usr.sbin/pim6sd/mtrace6/mtrace6.8
+++ b/usr.sbin/pim6sd/mtrace6/mtrace6.8
@@ -118,3 +118,7 @@ option is currently meaningless.
 The
 .Nm
 command first appeared in WIDE/KAME IPv6 protocol stack kit.
+.Pp
+IPv6 and IPsec support based on the KAME Project (http://www.kame.net/) stack
+was initially integrated into
+.Fx 4.0