+.BI "\-r," "" " \-\-reverse\-lookup"
+mountd tracks IP addresses in the rmtab, and when a DUMP request is made (by
+someone running showmount -a, for instance), it returns IP addresses instead
+of hostnames by default. This option causes mountd to do a reverse
+lookup on each IP address and return that hostname instead. Enabling this can
+have a substantial negative effect on performance in some situations.
+.TP