diff --git a/usr.sbin/mountd/exports.5 b/usr.sbin/mountd/exports.5
--- a/usr.sbin/mountd/exports.5
+++ b/usr.sbin/mountd/exports.5
@@ -25,7 +25,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd October 08, 2024
+.Dd December 16, 2024
 .Dt EXPORTS 5
 .Os
 .Sh NAME
@@ -84,6 +84,15 @@
 When exporting ZFS datasets with the
 .Sy sharenfs
 property, this is auomatically the case.
+If the
+.Fl alldirs
+flag is specified and
+the
+.Fl a
+command line option is specified for
+.Xr mountd 8 ,
+the export will fail if the directory path is not a local file system
+mount point.
 .Pp
 There are three forms of the directory path specification.
 The first is to list all mount points as absolute
@@ -550,12 +559,18 @@
 all its subdirectories.
 Since
 .Pa /cdrom
-is the conventional mountpoint for a CD-ROM device, this export will
-fail if no CD-ROM medium is currently mounted there since that line
+is the conventional mountpoint for a CD-ROM device,
+for the case where the
+.Fl a
+option has been specified for
+.Xr mountd 8 ,
+this export will
+fail if no CD-ROM medium is currently mounted there
+since that line
 would then attempt to export a subdirectory of the root file system
 with the
 .Fl alldirs
-option which is not allowed.
+option.
 The
 .Fl quiet
 option will then suppress the error message for this condition that