.SH "SYNOPSIS"
.
.B pathmtu
-.RB [ \-v ]
+.RB [ \-46v ]
.RB [ \-H
.IR header ]
.RB [ \-m
.B "\-u, \-\-usage"
Writes a brief usage summary to standard output and exits with status 0.
.TP
+.B "\-4"
+Look up hostnames only as IPv4 addresses.
+.TP
+.B "\-6"
+Look up hostnames only as IPv6 addresses.
+.TP
.BI "\-g, \-\-growth=" factor
Sets the retransmit interval growth factor. Each time a packet is
retransmitted,