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