Following up on a post a few days ago (node 67578) I am working on a 'telnet passthrough'. This is a process that connects to a server via telnet ( net::telnet) and also offers a standard socket ( io::socket ) for other users to connect to. Key presses are then passed from the socket to the telnet session and responses copied back. I developed the following on unix and it seems to work. I am surprised at that fact..... $switch is a telnet object (see switchConnect()) and I do 
print $switch $byte        # prints one byte to the telnet connection.
+  Confirmed as written by checking DUMP file
sysread($switch, $byte2, 1)    # reads in one byte from the telnet inp
+ut buffer.

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Can someone explaing why this works as $switch is not a filehandle. Now for the big problem. I have to get this running on a windows system running activeperl v5.6.1. Copied it over and everything has stopped working. boo hoo. the line from above has to be swapped to something like 
-print $switch $byte
+$switch->put($byte); ( telnet method )

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and the whole child/parent thing seems to stop working or deadlock. If I replace 
-while (sysread($switch, $byte2, 1))
-{
-    print $client $byte2;    
-}
+sleep(50)

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in the parent section things seem to start going again but obviously nothing it now coming back from the telnet console. What is going on ?? here's the program 
#!/opt/DKBperl/bin/perl
$|=1;
use IO::Socket;
use Net::Telnet;

#pass4.pl    <switchname> <port>

my($switch)=switchConnect($ARGV[0]);
my($server) = IO::Socket::INET->new( Proto => 'tcp', 
    LocalPort => $ARGV[1], 
    Listen => SOMAXCONN, 
    Reuse => 1); 
    
die "can't setup server" unless $server; 
while ($client = $server->accept()) 
{
    if (!defined($child_pid = fork())) 
    {
            die "cannot fork: $!";
    } 
    if($child_pid) 
    {
            print "I'm the parent $child_pid\n";            # REPLY
           # accept input from the telnet connection (switch) and copi
+es it to heroix (io::socket)
            while (sysread($switch, $byte2, 1))
            {
                print $client $byte2;    
            }
        kill("TERM" => $kidpid);        # send SIGTERM to child
        exit 0;
    } 
    else 
    {
             print "I'm the child $child_pid\n";    
             # accept input from heroix (io::socket) and copies it to 
+the telnet connection (switch)
             $client->autoflush(1); 
        while (sysread($client, $byte, 1))
        {
            $num=ord($byte);
            if($num==127) {$num=8};
            print $switch chr($num);
            }
        print "child exiting\n";
    } 
}

sub switchConnect 
{
    my($switchName)=@_;
    $t = new Net::Telnet()->new(    input_log    =>    "tmp/in",
                dump_log    =>    "tmp/dump",
                 Timeout     =>     10,
                output_log    =>    "tmp/out",
                errmode        =>    'return');

      print("Attempting to open switch $switchName..");
    $t->open(host=>$switchName);
    if(!$t->waitfor('/login:/'))
    {
        print "$hsgname seems engaged- exiting code 10\n";

        exit(10);
    }
    $t->print("admin");
    $t->waitfor('/Password:/');
    $t->print("santest1");
    if(!$t->waitfor('/\>/'))
    {
        print "Timeout on the password.  Is the password correct for $
+hsgname ? - exiting code 11\n";
        exit(11);
    }  
    print "..ok\n";
    return $t;
}

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update (broquaint): added a ending </b> tag and put a <readmore> tag before the main section of code

In reply to telnet passthrough 2 by wertert

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