Network scanning refers to a set of procedures that investigate a live host, the type of host, open ports, and the type of services running on the host. Network scanning is a part of intelligence gathering by virtue of which an attack can create a profile of the target organization.
In this chapter, we will cover the following topics:
How to check live systems
Ping sweep
TCP scanner
How to create an efficient IP scanner
Services running on the target machine
The Concept of a port scanner
How to create an efficient port scanner
You should have basic knowledge of the TCP/IP layer communication. Before proceeding further, the concept of the Protocol Data Unit (PDU) should be clear.
PDU is a unit of data specified in the protocol. It is the generic term for data at each layer.
For the application layer, PDU indicates data
For the transport layer, PDU indicates a segment
For the Internet or the network layer, PDU indicates a packet
For the data link layer or network access layer...