Perl Requires Chilkat v11.0.0+

TCP Socket through SSH Tunnel (Port Forwarding)

See more Socket/SSL/TLS Examples

Demonstrates using Chilkat Socket to communicate to a TCP service through an SSH tunnel. This example will connect to an NIST time server and (using the old Time Protocol (RFC 868)), will read the current GMT time.

Note: This is not necessarily a recommended means for getting the current date/time. The most commonly used time protocol is the Network Time Protocol (RFC-1305). The intent of this example is to show how TCP communications can occur through an SSH tunnel.

Perl

use chilkat();

$success = 0;

#  This example requires the Chilkat API to have been previously unlocked.
#  See Global Unlock Sample for sample code.

$tunnel = chilkat::CkSocket->new();

$sshHostname = "sftp.example.com";
$sshPort = 22;

#  Connect to an SSH server and establish the SSH tunnel:
$success = $tunnel->SshOpenTunnel($sshHostname,$sshPort);
if ($success == 0) {
    print $tunnel->lastErrorText() . "\r\n";
    exit;
}

#  Authenticate with the SSH server via a login/password
#  or with a public key.
#  This example demonstrates SSH password authentication.
$success = $tunnel->SshAuthenticatePw("mySshLogin","mySshPassword");
if ($success == 0) {
    print $tunnel->lastErrorText() . "\r\n";
    exit;
}

#  OK, the SSH tunnel is setup.  Now open a channel within the tunnel.
#  Once the channel is obtained, the Socket API may
#  be used exactly the same as usual, except all communications
#  are sent through the channel in the SSH tunnel.
#  Any number of channels may be created from the same SSH tunnel.
#  Multiple channels may coexist at the same time.

#  Connect to an NIST time server and read the current date/time
$maxWaitMs = 4000;
$useTls = 0;
$channel = chilkat::CkSocket->new();
$success = $tunnel->SshNewChannel("time-c.nist.gov",37,$useTls,$maxWaitMs,$channel);
if ($success == 0) {
    print $tunnel->lastErrorText() . "\r\n";
    exit;
}

#  The time server will send a big-endian 32-bit integer representing
#  the number of seconds since since 00:00 (midnight) 1 January 1900 GMT.
#  The ReceiveInt32 method will receive a 4-byte integer, but returns
#  1 or 0 to indicate success.  If successful, the integer
#  is obtained via the ReceivedInt property.
$bigEndian = 1;
$success = $channel->ReceiveInt32($bigEndian);
if ($success == 0) {
    print $channel->lastErrorText() . "\r\n";
    exit;
}

$dt = chilkat::CkDateTime->new();
$dt->SetFromNtpTime($channel->get_ReceivedInt());

#  Show the current local date/time
$bLocalTime = 1;
print "Current local date/time: " . $dt->getAsRfc822($bLocalTime) . "\r\n";

#  Close the SSH channel.
$success = $channel->Close($maxWaitMs);
if ($success != 1) {
    print $channel->lastErrorText() . "\r\n";
    exit;
}

#  It is possible to create a new channel from the existing SSH tunnel for the next connection:
#  Any number of channels may be created from the same SSH tunnel.
#  Multiple channels may coexist at the same time.
$success = $tunnel->SshNewChannel("time-a.nist.gov",37,$useTls,$maxWaitMs,$channel);
if ($success == 0) {
    print $tunnel->lastErrorText() . "\r\n";
    exit;
}

#  Review the LastErrorText to see that the connection was made via the SSH tunnel:
print $tunnel->lastErrorText() . "\r\n";

#  Close the connection to time-a.nist.gov.  This is actually closing our channel
#  within the SSH tunnel, but keeps the tunnel open for the next port-forwarded connection.
$success = $channel->Close($maxWaitMs);
if ($success != 1) {
    print $channel->lastErrorText() . "\r\n";
    exit;
}

#  Finally, close the SSH tunnel.
$success = $tunnel->SshCloseTunnel();
if ($success == 0) {
    print $tunnel->lastErrorText() . "\r\n";
    exit;
}

print "TCP SSH tunneling example completed." . "\r\n";