What is ICMP?
ICMP is an online layer protocol employed by network devices to diagnose network communication problems. the first use of ICMP is to work out whether or not the info reaches the intended destination as soon as possible. Typically, ICMP is employed on network devices, like routers.
ICMP isn’t a transport protocol that sends data between systems.
Although ICMP isn’t routinely utilized in end-user applications, it’s employed by network administrators to troubleshoot Internet connections in diagnostic utilities, including the ping and traceroute commands.
ICMP messages are transmitted as datagrams and contains an IP header that encapsulates the ICMP data. ICMP packets are IP packets with ICMP within the IP data part. ICMP messages also contain the complete IP header of the first message, therefore the end system knows which packet failed.
Does Telnet use ICMP?
No. Telnet is a TCP protocol.