ICMP stands for Internet Control Message Protocol, which is a protocol used by devices within a network to communicate problems with data transmission. ICMP is a network layer protocol that is used for reporting errors and performing network diagnostics. It is not typically used to exchange data between systems, nor is it regularly employed by end-user network applications. ICMP is used to determine if data is getting to its destination and at the right time, making it an important aspect of the error reporting process and testing to see how well a network is transmitting data. ICMP messages communicate information about network connectivity issues back to the source of the compromised transmission. ICMP messages are sent in several scenarios, such as when one device sends a message that is too large for the recipient to process, or when the network gateway finds a shorter route for the message to travel on. ICMP error messages report networking errors, such as unreachable destinations, timeouts, or fragmentation problems. ICMP is also used to execute distributed denial-of-service (DDoS) attacks.