scanner.pl

#!/usr/bin/perl

# TCP Port scanner

use IO::Socket;

# flush the print buffer immediately
$| = 1;

# Take input from user - hostname, start port , end port
print "Enter Target/hostname : ";

# Need to chop off the newline character from the input
chop ($target = <stdin>);
print "Start Port : ";
chop ($start_port = <stdin>);
&check_port($start_port);
print "End Port : ";
chop ($end_port = <stdin>);
&check_port($end_port);

# start the scanning loop
foreach ($port = $start_port ; $port <= $end_port ; $port++) 
{
	#\r will refresh the line
	print "\rScanning port $port";
	
	#Connect to port number
	$socket = IO::Socket::INET->new(PeerAddr => $target , PeerPort => $port , Proto => 'tcp' , Timeout => 1);
	
	#Check connection
	if( $socket )
	{
		print "\r = Port $port is open.\n" ;
	}
	else
	{
		#Port is closed, nothing to print
	}
}

print "\n\nFinished Scanning $target\n";

exit (0);

sub check_port {
    my $port = shift;

    if ($port =~ /\D+/ or $port > 65535 or $port < 0) {
        print "Please check the format of port: $port\n";
        exit 1;
    }
}