+.BI "\-g, \-\-growth=" factor
+Sets the retransmit interval growth factor. Each time a packet is
+retransmitted,
+.B pathmtu
+increases the amount of time it waits before retransmitting again by
+this
+.IR factor .
+The default growth factor is 3.
+.TP
+.BI "\-m, \-\-method=" name
+Select the MTU probing method. The available methods are shown by
+.BR \-\-help .
+The
+.B linux
+method is Linux-specific and might be confused by delayed errors under
+some circumstances, but it's usable by unprivileged users; the
+.B raw
+method is portable but requires
+.B pathmtu
+to be installed setuid-root.
+.TP
+.BI "\-r, \-\-retransmit=" interval
+Sets the initial retransmit interval, in seconds. If no reply is
+received to a probe within the interval, then a second packet is sent,
+and the retransmit interval increased by the growth factor (see
+.BR \-g ).
+The default initial retransmit interval is 0.333 seconds.
+.TP