#!/usr/bin/perl

use warnings;
use strict;

use IO::Socket;
use IPC::Open3;

my $sock = new IO::Socket::INET (
        LocalHost => '127.0.0.1',
        LocalPort => '1818',
        Proto => 'tcp',
        Listen => 1,
        ReuseAddr => 1,
        Timeout => 20
);

die "Could not create socket: $!\n" unless $sock;

## THIS WORKS (I can telnet to port 1818 from another terminal & see the text come across):
#my $new_sock = $sock->accept() or die "No one came!";
#while ( <$new_sock> ) { print; }

## THIS WORKS (If I type "cat | ./<this_script>, I can type and see it echo back):
#my $pid = open3( "<&STDIN", ">&STDOUT", ">&STDERR", "/bin/cat" );
#waitpid( $pid, 0 );

# THIS DOES NOT WORK (using open3 to read from a network handle). 
my $new_sock = $sock->accept() or die "No one came!";
#my $pid = open3( $new_sock, ">&STDOUT", ">&STDERR", "/bin/cat" ); # can telnet to port but immediately disconnected
my $pid = open3( $new_sock, $new_sock, ">&STDERR", "/bin/cat" ); # can telnet to port but immediately disconnected
waitpid( $pid, 0 );

close($sock);