Check for open ports on computer

1. Linux
        Create a file on console steps below
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$ nano portscan.sh
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#!/bin/bash
nmap -sS -O ip.address.off.the.server


Save the file

$chmod 777 portscan.sh
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Basically you can just run the command much simpler $ nmap -sS -O ip.address.off.the.server
It will output
PORT     STATE SERVICE
22/tcp   open  ssh
80/tcp   open  http
443/tcp  open  https
1241/tcp open  nessus

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--- the scanning is for open ports since all ports are closed in linux ---


in windows create a batch file c:\>copy con portscan.bat

paste inside:         netstat -a | find "LISTENING"
save the file

-- NOTE THIS IS if you are inside the machine ---