Ethical Hacking: Techniques, Tools, and Countermeasures, 4th Edition

Mapping Open Ports

Once an attacker completes the port scanning phase, the next logical step is to map the target network. An attack in this stage has moved to a more interactive and aggressive approach. Many different tools can be used to map open ports and identify services running on servers in a target network. In the discussion here, we will focus on the most commonly used tools. No matter which tools are to be used, however, the activity at this point can be boiled down to determining whether a target is online and then discovering open ports and running services on the target.

Nmap

Nmap (Network Mapper) is one of the most widely used security tools, and a firm understanding of this utility is a basic requirement for security professionals. ...