What is Nmap

Nmap ("Network Mapper") is a free and open source (license) utility for network discovery and security auditing. Many systems and network administrators also find it useful for tasks such as network inventory, managing service upgrade schedules, and monitoring host or service uptime. Nmap uses raw IP packets in novel ways to determine what hosts are available on the network, what services (application name and version) those hosts are offering, what operating systems (and OS versions) they are running, what type of packet filters/firewalls are in use, and dozens of other characteristics. It was designed to rapidly scan large networks, but works fine against single hosts. Nmap runs on all major computer operating systems, and official binary packages are available for Linux, Windows, and Mac OS X. In addition to the classic command-line Nmap executable, the Nmap suite includes an advanced GUI and results viewer (Zenmap), a flexible data transfer, redirection, and debugging tool (Ncat), a utility for comparing scan results (Ndiff), and a packet generation and response analysis tool (Nping).

Nmap was named “Security Product of the Year” by Linux Journal, Info World, LinuxQuestions.Org, and Codetalker Digest. It was even featured in twelve movies, including The Matrix Reloaded, Die Hard 4, Girl With the Dragon Tattoo, and The Bourne Ultimatum.

Nmap is ...

• Flexible: Supports dozens of advanced techniques for mapping out networks filled with IP filters, firewalls, routers, and other obstacles. This includes many port scanning mechanisms (both TCP & UDP), OS detection, version detection, ping sweeps, and more. See the documentation page.
• Powerful: Nmap has been used to scan huge networks of literally hundreds of thousands of machines.
• Portable: Most operating systems are supported, including Linux, Microsoft Windows, FreeBSD, OpenBSD, Solaris, IRIX, Mac OS X, HP-UX, NetBSD, Sun OS, Amiga, and more.
• Easy: While Nmap offers a rich set of advanced features for power users, you can start out as simply as "nmap -v -A targethost". Both traditional command line and graphical (GUI) versions are available to suit your preference. Binaries are available for those who do not wish to compile Nmap from source.
• Free: The primary goals of the Nmap Project is to help make the Internet a little more secure and to provide administrators/auditors/hackers with an advanced tool for exploring their networks. Nmap is available for free download, and also comes with full source code that you may modify and redistribute under the terms of the license.
• Well Documented: Significant effort has been put into comprehensive and up-to-date man pages, whitepapers, tutorials, and even a whole book! Find them in multiple languages here.
• Supported: While Nmap comes with no warranty, it is well supported by a vibrant community of developers and users. Most of this interaction occurs on the Nmap mailing lists. Most bug reports and questions should be sent to the nmap-dev list, but only after you read the guidelines. We recommend that all users subscribe to the low-traffic nmap-hackers announcement list. You can also find Nmap on Facebook and Twitter. For real-time chat, join the #nmap channel on Freenode or EFNet.
• Acclaimed: Nmap has won numerous awards, including "Information Security Product of the Year" by Linux Journal, Info World and Codetalker Digest. It has been featured in hundreds of magazine articles, several movies, dozens of books, and one comic book series. Visit the press page for further details.
• Popular: Thousands of people download Nmap every day, and it is included with many operating systems (Redhat Linux, Debian Linux, Gentoo, FreeBSD, OpenBSD, etc). It is among the top ten (out of 30,000) programs at the Freshmeat.Net repository. This is important because it lends Nmap its vibrant development and user support communities.

Overview of Network Discovery

Network Discovery is a Windows setting that determines whether other computers and devices connected to the network can see and communicate with each other. When enabled on your PC, you’ll be able to see other computers and devices connected to the same network. When disabled, on the other hand, you won’t be able to see other computers or devices connected to the same network, nor will those connected computers or devices be able to see your PC.

You can enable Network Discovery by accessing Settings > Network & Internet > Wi-Fi > Change Advanced Sharing Option. Next, click the network labeled “Private” so that it expands. You can then select the option to turn on Network Discovery. When finished, click “Save Changes” to complete the process.

Advantages of Enabling Network Discovery

Network Discovery does more than allow you to see other computers and devices connected to the same network; it allows you to communicate with the connected computers or devices. You use Network Discovery to print documents over a network. Even if a computer isn’t physically connected to a printer via a cable, you can still print documents if they are both on the same on the network and this Windows feature is enabled.

In addition to shared printing, Network Discovery allows you to transfer files between two or more computers or devices on the network. Of course, you can always transfer files over the internet, but Network Discovery makes it easier by allowing you to transfer files directly over Wi-Fi.

Disadvantages of Enabling Network Discovery

With Network Discovery enabled, data transmitted between the connected computers or devices could be intercepted by a third party. Network sniffing, for example, is a cyber threat in which a hacker intercepts data transmitted over a network. If you have Network Discovery enabled, a hacker could steal data as it’s transmitted between the computers or devices.

With that said, network sniffing shouldn’t be a problem if you use a strong encryption for your network. Wi-Fi Protected Access 2, or what’s more commonly known simply as WPA2, is arguably the most secure encryption protocol for Wi-Fi networks, making it an excellent choice if you’re planning to use Network Discovery.