Nmap has been created by Fyodor.It is a major security tool.The Nmap includes features like port scanning,TCP Scan,UDP Scan,Syn Scan,OS Fingerprinting.
In this article we will cover some basic nmap features:
- First go to nmap.org and download nmap & install it.
- Then go to command prompt & type nmap.
- This will show you basic nmap help.
Type nmap 127.0.0.1(scanning our own machine) and press enter
The results are
Now lets focus on ports which are open
PORT STATE SERVICE
111/TCP Open rpcbind
631/tcp Open ipp
Now lets do a UDP scan.
nmap 127.0.0.1 -sU
This will test for UDP scan.
Since UDP is connectionless protocol and so the packets may be lost during transaction. The state of ports reported by nmap in a UDP scan is either open/filtered.
If the packet sent doesnt return then packet may be filtered by the destination or the port may be closed in the case of the UDP Scan.
In nmap you can specify IP Address as a parameter instead of specifying host name directly.
To look for IP Address from the host name follow these steps.
Open command prompt
Type nslookup <host name>
Eg. Nslookup www.abc.com
Lets assume that the address is somewhat 18.104.22.168
Now type nmap 22.214.171.124
The result would be same.
Let us take another example.
nmap –vv 127.0.0.1
-vv stands for very verbose(It gives detailed info about the target host)
and it does a more comprehensive scan.
Now lets do OS fingerprinting for localhost.(OS fingerprinting allows to detect the Operating System on the system)
Type nmap -O 127.0.0.1
This -O option is likely to tell which OS might be running on the remote system.
Hope you find this basic tutorial useful.