Use Switches like nmap -sO,nmap -sS,nmap -p,nmap -T4,nmap -sF
Network mapper is best LAN network scanner tool by comes with Kali Linux. It has switches like -T4 -sS -sF -sO -v -p -pE -pA -pU -n
Oh yes! you are seeking what is switches?
It has lots of sub tools. that is excuted by using switch. Like if we are going to scan particular IP address and we run command nmap 192.168.56.102 (Target IP Address) It scan network through default options. When we specify any switch like nmap -v the process will be verbose.
One more question how will you see available options?
It is very simple run following command to see available options and how can you use them!
nmap -h OR namp –help
Timing option T4 nmap -T4
In scanning process nmap sends packets to the target machine within particular time period (interval). If you want to decrease or increase this time period then you can use nmap -T switch. but -T option required an attribute, means you should use 1,2,3,4 as per requirement T4 has fast speed then T1, T2 and T4.
nmap -T4 192.168.56.102
TCP SYN Scan nmap –sS
It is required privilege access and identifies TCP ports. The TCP SYN Scan implements common method to identify open ports without completing Three way handshake process. When the open port is detected, the TCP handshake reset before completing. So this scanning also known as Half Open scanning.
nmap -sS 192.168.56.102
FIN Scan nmap -sF
FIN scan sends packet with FIN flag to the target machine, so these frames are unusual because the they sent to destination before completing Three way handshaking process. If the tcp session is not active, it means that port is formally closed. If the particular port is closed on the target machine it reverse RST packet in the response of FIN Scan.
nmap -sF 192.168.56.102
IP Protocol scan has miner difference for other nmap scans. It is searching for additional IP protocols used by Target machine for example ICMP, TCP and UDP. If you scans Router, may be detected additional IP protocols like EGP or IGP.
nmap -sO 192.168.56.102
Verbose Mode nmap –v
Nmap’s verbose mode provides the feature of obtaining additional detail in the scan output. The verbose mode doesn’t change what occurs during the scan, it only changes the amount of information that nmap displays on its output.
Port Scan nmap -p
Nmap mostly used for scanning ports, by default it scans all ports but you can scan single, multiple or within range protocols.
Single port scan: namp -p21 192.168.56.102
Multiple scan ports: namp -p21, 80, 443 192.168.56.102
scan Ports Range: nmap -p20-1000
ICMP Echo Request Ping Nmap –PE
The ICMP echo request ping sends an ICMP echo request to the target machine’s IP address. In the normal type of ICMP echo request is sent combination TCP and ACK ping.With the option –PE , the ICMP echo request can be specified as the nmap ping method without pairing TCP ACK ping.
nmap -PE 192.168.56.102
TCP ACP Ping nmap –PA
Instead of using the default option of both an ICMP echo request and a TCP ACK, the –PA option sends a TCP ACK and forgoes any ICMP echo requests. This is a good alternative when the use of ICMP is not applicable because of packet filtering or firewalls.
nmap -PA 192.168.56.102