Nmap is a command line tool for network exploration or security auditing. It supports ping scanning (determine which hosts are up), many port scanning techniques (determine what services the hosts are offering), and TCP/IP fingerprinting (remote host operating system identification).
Installation
To install nmap for Debian and Ubuntu Linux based server systems type the following apt-get command:
$ sudo apt-get install nmap
Sample outputs:
Reading package lists... Done Building dependency tree Reading state information... Done The following NEW packages will be installed: nmap 0 upgraded, 1 newly installed, 0 to remove and 2 not upgraded. Need to get 1,643 kB of archives. After this operation, 6,913 kB of additional disk space will be used. Get:1 http://mirrors.service.networklayer.com/ubuntu/ precise/main nmap amd64 5.21-1.1ubuntu1 [1,643 kB] Fetched 1,643 kB in 0s (16.4 MB/s) Selecting previously unselected package nmap. (Reading database ... 56834 files and directories currently installed.) Unpacking nmap (from .../nmap_5.21-1.1ubuntu1_amd64.deb) ... Processing triggers for man-db ... Setting up nmap (5.21-1.1ubuntu1) ...
Examples
To find the nmap version, enter:
# nmap -V
OR
# nmap --version
Sample outputs:
Nmap version 5.21 ( http://nmap.org )
WARNING! nmap scan could get you into legal trouble if you don’t have permission to scan the target systems.To scan an IP address, enter:
# nmap 192.168.1.2
Sample outputs:
Starting Nmap 5.00 ( http://nmap.org ) at 2012-11-18 14:41 IST Interesting ports on 192.168.1.2: Not shown: 997 closed ports PORT STATE SERVICE 23/tcp open telnet 53/tcp open domain 80/tcp open http MAC Address: 74:44:01:40:57:FB (Unknown) Nmap done: 1 IP address (1 host up) scanned in 1.28 seconds |
To scan a range of IP addresses, enter:
# nmap 192.168.1.2-10
To scan an entire subnet:
# nmap 192.168.1.0/24
More examples:
## Ping only scan ## nmap -sP 192.168.1.2 ## Scan and do traceroute ## nmap --traceroute IP-ADDRESS nmap --traceroute DOMAIN-NAME-HERE ## TCP SYN Scan ## nmap -sS 192.168.1.2 ## UDP Scan ## nmap -sU 192.168.1.2 ## IP protocol scan ## nmap -sO 192.168.1.2 ## Scan port 80, 25, 443 ## nmap -p 80 192.168.1.2 nmap -p http 192.168.1.2 nmap -p 25 192.168.1.2 nmap -p smtp 192.168.1.2 nmap -p 443 192.168.1.2 nmap -p 80,24,443 192.168.1.2 ## Scan port ranges ## nmap -p 512-1024 192.168.1.2 ## Scan for OS i.e. Operating System Detection ## nmap -O 192.168.1.2 nmap -O --osscan-guess 192.168.1.2 ## Scan for application server version ## nmap -sV 192.168.1.2 |
Type the following command to read nmap man page:
# man nmap