--- sbin/mount_nfs/mount_nfs.8.orig	2019-06-11 15:30:08.090594000 -0400
+++ sbin/mount_nfs/mount_nfs.8	2019-06-11 15:34:01.306130000 -0400
@@ -157,7 +157,16 @@
 .Dq "host" ,
 .Dq "nfs"
 or
-.Dq "root" .
+.Dq "root" ,
+although the form
+.Sm off
+.Aq Ar service
+@
+.Aq Ar fqdn
+.Sm on
+can also be used if the local system's
+.Xr gethostname 3
+value does not match the host-based principal in the keytab.
 .It Cm hard
 Same as not specifying
 .Cm soft .