Question

Header size of the ICMP message is _________

(a) 8-bytes

(b) 8-bits

(c) 16-bytes

(d) 16-bits

The question was posed to me at a job interview.

This intriguing question originated from ICMP in section TCP/IP Protocol Suite of Computer Network

Answer 1

Right option is (a) 8-bytes

To explain I would say: An ICMP message has an 8-byte header and a variable size data section. Out of the 8 bytes, the first 4 bytes are of a fixed format having the type, code and checksum fields and the next 4 bytes depend upon the type of the message.