diff --git a/sbin/mount_nfs/mount_nfs.8 b/sbin/mount_nfs/mount_nfs.8
index 5328beab8f21..d5245feff96f 100644
--- a/sbin/mount_nfs/mount_nfs.8
+++ b/sbin/mount_nfs/mount_nfs.8
@@ -99,6 +99,9 @@ be a multiple of DIRBLKSIZ that is <= the read size for the mount.
 Pass Kerberos authenticators to the server for client-to-server
 user-credential mapping.
 This requires that the kernel be built with the NFSKERB option.
+The use of this option will prevent the kernel from compiling
+unless calls to the appropriate Kerberos encryption routines
+are provided in the NFS source.
 (Refer to the INTERNET-DRAFT titled
 .%T "Authentication Mechanisms for ONC RPC" ,
 for more information.)
diff --git a/sbin/mountd/exports.5 b/sbin/mountd/exports.5
index 93a07947f9b2..b5fff27d3cd4 100644
--- a/sbin/mountd/exports.5
+++ b/sbin/mountd/exports.5
@@ -148,6 +148,9 @@ The
 option specifies that the Kerberos authentication server should be
 used to authenticate and map client credentials.
 This option requires that the kernel be built with the NFSKERB option.
+The use of this option will prevent the kernel from compiling
+unless calls to the appropriate Kerberos encryption routines
+are provided in the NFS source.
 .Pp
 The
 .Fl ro
diff --git a/usr.sbin/mountd/exports.5 b/usr.sbin/mountd/exports.5
index 93a07947f9b2..b5fff27d3cd4 100644
--- a/usr.sbin/mountd/exports.5
+++ b/usr.sbin/mountd/exports.5
@@ -148,6 +148,9 @@ The
 option specifies that the Kerberos authentication server should be
 used to authenticate and map client credentials.
 This option requires that the kernel be built with the NFSKERB option.
+The use of this option will prevent the kernel from compiling
+unless calls to the appropriate Kerberos encryption routines
+are provided in the NFS source.
 .Pp
 The
 .Fl ro