Port scanning with Nmap (UDP, stealth, connect, zombie)
Nmap can be utilized to perform UDP, TCP stealth, TCP connect, and zombie scans. In this section, we will discuss how to conduct each of these types of scans. The Nmap approach to UDP scanning is more complex and attempts to identify live services by injecting service-specific probe requests in an effort to solicit a positive response that confirms the existence of a given service. We will also discuss how Nmap handles stealth and TCP connect scanning. Finally, we will look at a highly effective scanning mode Nmap has for zombie scanning.
Getting ready
To use Nmap to perform UDP, TCP stealth, TCP connect, or zombie scans, you will need to have a remote system that is running network services over UDP and TCP. In the examples provided, an instance of Metasploitable2 is used as a scan target, and an installation of Windows XP is used as an incremental IPID zombie. In the examples provided, a combination of Linux and Windows systems is used...