WHAT IS ICMP
ICMP is not unfimiliar to us those had learned the book: Network of Computer. But we still can`t understand its structure and more deeper content.
ICMP,short for Internet Control Message Protocol,work in network layer,do duty for more efficient fowarding IP datagram and impoving the success rate of message delivering.
The structure of ICMP is below here:
It`s first four byte is fixed format:the bit 0 to bit 7 mean the TYPE,bit 8 to bit 15 means the CODE,and the rest 16 bits used for check sum.