Installation

• Linux

apt-get install nmap

• Windows. Download the msi package

scan a computer to see the open port ?

nmap -v -A scanme.nmap.org

scan a network ?

From ZenMap, choose the scan that you want to perform and change the value of <target> by for instance for a 255.255.255.0 subnetmask 192.168.1.1/24 and click on the scan button.

define the port

You define the port with the p verbose.

For example, the argument -p U:53,111,137,T:21-25,80,139,8080 would scan:

• UDP ports 53, 111,and 137,
• the TCP ports 21 to 25 and the listed one 80, 139, 8080

Example with the port:

• http 80,
• https 443,
• oracle listener 1521
• and Obiee Presentation Service 9704

nmap -Pn -p T:80,443,1521,9704 sz0057.app.gen.local
# for ipv6, you need to add the 6 property and the target (as name or ip)
nmap -6 2a09:8280:1::42:92ef

where:

• Pn threat the machine as up (in case of no ping is possible)
• p defines the port

Output:

Starting Nmap 5.51 ( http://nmap.org ) at 2011-12-16 10:36 W. Europe Standard Time
Nmap scan report for obiee.gerardnico.local
Host is up (0.074s latency).
PORT     STATE    SERVICE
80/tcp   closed   http
443/tcp  filtered https
1521/tcp closed   oracle
9704/tcp open     unknown
MAC Address: 00:FF:93:3A:10:89 (Unknown)

Nmap done: 1 IP address (1 host up) scanned in 15.07 seconds