NAME

icmp — internet control message protocol

SYNOPSIS

#include <sys/socket.h>
#include <netinet/in.h>

DESCRIPTION

The Internet Control Message Protocol (ICMP) is a control and error reporting layer for the Internet Protocol version 4 ip(4). ICMP is commonly used to diagnose network problems, such as the destination being unreachable, network congestion, packets exceeding their time to live, and so on.

SEE ALSO

inet(4), ip(4), ping(4), kernel(7)

STANDARDS

J. Postel (ed.), Internet Control Message Protocol - DARPA Internet Program Protocol Specification, STD 5, RFC 792, USC/Information Sciences Institute, September 1981.

BUGS

ICMP is not implemented yet, except automatically replying to the Echo Request message (ping) and the existence of ping(4) sockets for sending Echo Request messages and receiving Echo Reply messages.