How do I write a simple PERL script to scan for open ports on a target machine

Question

I’m learning about network security and I want to create a simple port scanner using Perl. My goal is to scan a target machine and identify open ports. I’ve worked with Net::Ping in Perl before, but I’m not sure how to implement a basic port scan to check for open TCP ports on a range of IP addresses or a specific host.

Could someone provide a basic example of how I could write such a script? I’m interested in understanding how the code works, especially when it comes to handling connection attempts and timeouts.

Answer 1

In order to create a simple PERL script that can scan for open ports on a target machine, we can use the IO::Socket::INET module.

This module helps us to connect to specific ports and check whether they're open.

Here's a bash script that scans for a range of TCP ports on a target machine:

use strict;
use warnings;
use IO::Socket::INET;

my $target = '192.168.1.1';
my $start_port = 1;
my $end_port = 1000;

for my $port ($start_port .. $end_port) {
    my $socket = IO::Socket::INET->new(
        PeerAddr => $target,
        PeerPort => $port,
        Proto    => 'tcp',
        Timeout  => 2
    );
    if ($socket) {
        print "Port $port is open\n";
        close($socket);
    }
}

This bash script will check each port within the specified range and if any connection is made within the timeout period, the port is reported as open.