Explanation/Reference: https://www.sans.org/reading-room/whitepapers/threats/icmp-attacks-illustrated-477 In a nutshell, these are types of attacks belonging to "Reconnaissance and scanning" category: – ICMP sweep traceroute inverse mapping OS fingerprinting firewalk And here are types of attacks used in the "Exploits" category: ICMP route redirect ICMP informational messages ICMP router discovery messages ICMP floods