Project Toolkit 003 : Nmap

What does Nmap do?

Nmap is a tool that gives you detailed, real-time information about your network and the devices that are connected to it. Nmap’s principal functions can be divided into three categories. The tool first provides thorough information about each IP active on your networks, after which each IP can be inspected. This helps managers to determine whether an IP address is being used by a legitimate service or by a malicious outsider. Secondly, Nmap gives you information about your whole network. It can be used to display a list of active hosts and open ports, as well as identify the operating system of all network devices. This makes it an important aspect of pentesting as well as a handy tool for ongoing system monitoring. For example, it’s used in the Metasploit framework to probe and then fix network vulnerabilities. Finally, Nmap has shown to be a useful tool for users who want to secure their personal and professional websites. When you use Nmap to scan your own web server, especially if you’re hosting your website from home, you’re essentially imitating a hacker’s attack. This type of “attacking” on your own site is a great approach to find security flaws.

How to install Nmap?

The installation of Nmap is simple, although it varies depending on your operating system.

How to run a ping scan?

Without sending any packers to these hosts, this identifies all the the IP addresses that are currently online.

How to run a host scan?

Using Nmap to run a host scan is a more powerful technique to scan your networks. A host scan, unlike a ping scan, sends ARP request packets to all of the hosts on your network. Each host then responds with another ARP packet including its status and MAC address in response to this packet.

Common Nmap Functions.

01. Ping scanning.

02. Port scanning

TCP-SYN-Scan (-sS)
TCP-Connect-Scan (-sT)
UDP-Scan (-sU)
IP-Protocol-Scan (-sO)

The basic port states that Nmap distinguishes are stated below;

· open

03. Host scanning

04. OS scanning

Nmap’s OS scanning is one of its most powerful functions. Nmap does this type of scan by sending TCP and UDP packets to a certain port and then analyzing the response. It compares the response to a database of 2600 operating systems and returns information on the host’s operating system (and version).

05. Disable DNS name resolution

Finally, by using the -n argument to suppress reverse DNS resolution, you can speed up your Nmap scans. If you need to scan a huge network, this can be quite handy.



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