--- /dev/null
+This extension can be used if `--protocol icmp' is specified. It
+provides the following option:
+.TP
+[\fB!\fP] \fB--icmp-type\fP \fItypename\fP
+This allows specification of the ICMP type, which can be a numeric
+ICMP type, or one of the ICMP type names shown by the command
+.nf
+ iptables -p icmp -h
+.fi