It can be with Type or Description ICMP Message Types Description ICMP Message Types: ex: iptables -I INPUT -p icmp --icmp-type echo-request -s 1.2.3.4 -j ACCEPT Type:  ex: iptables -I INPUT -p icmp --icmp-type 8 -s 1.2.3.4 -j ACCEPT ICMP Message Types The type field identifies the type of the message sent by the host or gateway. Many of … Continue reading Allow icmp with specific Message Types