The Nmap

The Nmap aka Network Mapper is an open
source and a very versatile tool for Network
administrators. Nmap is used for exploring
networks, perform security scans, network
audit and finding open ports on remote
machine. It scans for Live hosts, Operating
systems, packet filters and open ports
running on remote hosts.
Scan a System with Hostname and IP Address
1.Scan using Hostname
nmap server2.tecmint.com
2.Scan using IP Address
nmap 192.168.0.101
3.Scan using “-v” option ( “-v” option is
giving more detailed information about the
remote machine. )
map -v server2.tecmint.com
4.Scan Multiple Hosts
map 192.168.0.101 192.168.0.102
192.168.0.103
5.Scan a whole Subnet
nmap 192.168.0.*
6.Scan Multiple Servers using last octet of IP
address
nmap 192.168.0.101,102,103
7.Scan an IP Address Range
nmap 192.168.0.101-110
8.Scan Network Excluding Remote Hosts
nmap 192.168.0.* --exclude 192.168.0.100
9.Scan OS information and Traceroute
nmap -A 192.168.0.101
10.Enable OS Detection with Nmap
nmap -O server2.tecmint.com
11.Scan a Host to Detect Firewall
nmap -sA 192.168.0.101
12.Scan a Host to check its protected by
Firewall
nmap -PN 192.168.0.101
13.Find out Live hosts in a Network
nmap -sP 192.168.0.*
14.Perform a Fast Scan
nmap -F 192.168.0.101
15.Find Nmap version
nmap -V
16.Scan Ports Consecutively
nmap -r 192.168.0.101
17.Print Host interfaces and Routes
nmap --iflist
18.Scan for specific Port
nmap -p 80 server2.tecmint.com
19.Scan a TCP Port
nmap -p T:8888,80 server2.tecmint.com
20.Scan a UDP Port
nmap -sU 53 server2.tecmint.com
21.Scan Multiple Ports
nmap -p 80,443 192.168.0.101
22.Scan Ports by Network Range
nmap -p 80-160 192.168.0.101
23.Find Host Services version Numbers
nmap -sV 192.168.0.101
24.Scan remote hosts using TCP ACK (PA) and
TCP Syn (PS)
nmap -PS 192.168.0.101
25.Scan Remote host for specific ports with
TCP ACK
nmap -PA -p 22,80 192.168.0.101
26.Scan Remote host for specific ports with
TCP Syn
nmap -PS -p 22,80 192.168.0.101
27.Perform a stealthy Scan
nmap -sS 192.168.0.101
28.Check most commonly used Ports with
TCP Syn
nmap -sT 192.168.0.101
29.Perform a tcp null scan to fool a firewall
nmap -sN 192.168.0.101
Download link :- http://nmap.org/
download.html