I am doing a netwotk programming job,and have some questions about the ICMP.
what is the purpose of this protocol? when a packet of ICMP was sent,how does it travel,in TCP or UDP?
thanks for your help.
I don't know how this packet travels in TCP or UDP but I can tell what this is all about.
ICMP is Internet Control Messaging Protocol. It's used through out IP n/w. ICMP was designed to provide 4 feedbacks that are used to make IP routing efficient.
1. Reachability
2. Redirect
3. Timeouts
4. Router discovery
ICMP is used for control and messaging over network.
Ping is one of the common applications of ICMP. it can also be used for tracing the path in network. Thats how Trace Route program is working. The presence of a host can be verified by ICMP. But it always possible to hide your presence by blocking ICMP selectively using firewalls like IP Filter or Norton Internet Scecurity, its just a per host configuration.