#!/usr/bin/perl
use IO::Socket;
my ($line, $port, $sock, @servers);
my $VERSION='1.0';

($server = $ARGV[0]) || &usage;
$begin = ($ARGV[1] || 0);

for ($port=$begin;$port<=65000;$port++)	{
	$sock = IO::Socket::INET->new(PeerAddr => $server,
				 	PeerPort => $port,
				 	Proto => 'tcp');
	if ($sock)	{
		print "Connected on port $port\n";
	} else {
		# print "$port failed\n";
	}
}  #  End for

sub usage	{
	print "Usage: portscan hostname [start at port number]\n";
	exit(0);
}

=head1 NAME

portscan - Scans a host on TCP ports to determine what is listening

=head1 DESCRIPTION

Determines on which TCP ports a host is listening for incoming connections.
Useful for determining what services are running on a server.

=head1 PREREQUISITE

uses IO::Socket

=head1 COREQUISITE

None

=head1 README

Determines on which TCP ports a host is listening for incoming connections.
Useful for determining what services are running on a server.

=pod OSNAMES

MSWin32, Unix

=pod SCRIPT CATEGORIES

Networking

=cut