Glossary: Compliance, Privacy and Penetration Testing

ICMP

Also written: Internet Control Message Protocol

Internet Control Message Protocol: the protocol networks use to send error and control messages. An ICMP 'unreachable' reply, or no reply at all, makes Nmap report a port as filtered.

Where the book teaches it

Chapter 5: Penetration Testing

Related terms

Port state (open, closed, filtered)Nmap