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Chapter 15. Nmap Reference Guide
## Chapter 15. Nmap Reference Guide ## Name nmap — Network exploration tool and security / port scanner `nmap` [ `Scan Type` ...] [ `Options` ] { `target specification` } ## Description
| Note
This document describes the very latest version of Nmap available from http://nmap.org/download.html or http://nmap.org/dist/?C=M&O=D Please ensure you are using the latest version before reporting that a feature doesn't work as described.
Nmap (“Network Mapper”) is an open source tool for network exploration and security auditing. It was designed to rapidly scan large networks, although it works fine against single hosts. 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. While Nmap is commonly used for security audits, many systems and network administrators find it useful for routine tasks such as network inventory, managing service upgrade schedules, and monitoring host or service uptime. The output from Nmap is a list of scanned targets, with supplemental information on each depending on the options used. Key among that information is the “interesting ports table”. That table lists the port number and protocol, service name, and state. The state is either `open`, `filtered`, `closed`, or `unfiltered`. Open means that an application on the target machine is listening for connections/packets on that port. `Filtered` means that a firewall, filter, or other network obstacle is blocking the port so that Nmap cannot tell whether it is `open` or `closed`. `Closed` ports have no application listening on them, though they could open up at any time. Ports are classified as `unfiltered` when they are responsive to Nmap's probes, but Nmap cannot determine whether they are open or closed. Nmap reports the state combinations `open|filtered` and `closed|filtered` when it cannot determine which of the two states describe a port. The port table may also include software version details when version detection has been requested. When an IP protocol scan is requested (`-sO`), Nmap provides information on supported IP protocols rather than listening ports. In addition to the interesting ports table, Nmap can provide further information on targets, including reverse DNS names, operating system guesses, device types, and MAC addresses. A typical Nmap scan is shown in Example 15.1, “A representative Nmap scan” The only Nmap arguments used in this example are `-A`, to enable OS and version detection, script scanning, and traceroute; `-T4` for faster execution; and then the two target hostnames. Example 15.1. A representative Nmap scan
    # nmap -A -T4 scanme.nmap.org playground

    Starting nmap ( http://nmap.org )
    Interesting ports on scanme.nmap.org (205.217.153.62):
    (The 1663 ports scanned but not shown below are in state: filtered)
    PORT    STATE  SERVICE VERSION
    22/tcp  open   ssh     OpenSSH 3.9p1 (protocol 1.99)
    53/tcp  open   domain
    70/tcp  closed gopher
    80/tcp  open   http    Apache httpd 2.0.52 ((Fedora))
    113/tcp closed auth
    Device type: general purpose
    Running: Linux 2.4.X|2.5.X|2.6.X
    OS details: Linux 2.4.7 - 2.6.11, Linux 2.6.0 - 2.6.11
    Uptime 33.908 days (since Thu Jul 21 03:38:03 2005)

    Interesting ports on playground.nmap.org (192.168.0.40):
    (The 1659 ports scanned but not shown below are in state: closed)
    PORT     STATE SERVICE       VERSION
    135/tcp  open  msrpc         Microsoft Windows RPC
    139/tcp  open  netbios-ssn
    389/tcp  open  ldap?
    445/tcp  open  microsoft-ds  Microsoft Windows XP microsoft-ds
    1002/tcp open  windows-icfw?
    1025/tcp open  msrpc         Microsoft Windows RPC
    1720/tcp open  H.323/Q.931   CompTek AquaGateKeeper
    5800/tcp open  vnc-http      RealVNC 4.0 (Resolution 400x250; VNC port: 5900)
    5900/tcp open  vnc           VNC (protocol 3.8)
    MAC Address: 00:A0:CC:63:85:4B (Lite-on Communications)
    Device type: general purpose
    Running: Microsoft Windows NT/2K/XP
    OS details: Microsoft Windows XP Pro RC1+ through final release
    Service Info: OSs: Windows, Windows XP

    Nmap finished: 2 IP addresses (2 hosts up) scanned in 88.392 seconds
Using Customized Data Files |  | Options Summary
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