Nmap works at the OSI Network layer and Transport layer. We have to remember that each layer has its own:
- header section
- data section
We remember that the Network Layer is the one responsible for the movement or routing of packets across the network, the protocol used on internet at this layer is the "IP" (Internet Protocol).
The Transport layer provides the flowof data between two hosts, for the application layer above. Examples of protocols at this layer are:
- Internet Control Message Protocol (ICMP)
- User Datagram Protocol (UDP)
- Transmission Control Protocol (TCP)