PHP 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.

Chilkat2 PHP

<?php

use Chilkat2\DateTime;
use Chilkat2\Socket;

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

$tunnel = new Socket();

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

// Connect to an SSH server and establish the SSH tunnel:
try {
    $tunnel->SshOpenTunnel($sshHostname, $sshPort);

    // Authenticate with the SSH server via a login/password
    // or with a public key.
    // This example demonstrates SSH password authentication.
    $tunnel->SshAuthenticatePw('mySshLogin', 'mySshPassword');

    // 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 = false;
    $channel = new Socket();
    $tunnel->SshNewChannel('time-c.nist.gov', 37, $useTls, $maxWaitMs, $channel);

    // 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
    // true or false to indicate success.  If successful, the integer
    // is obtained via the ReceivedInt property.
    $bigEndian = true;
    $channel->ReceiveInt32($bigEndian);
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

$dt = new DateTime();
$dt->SetFromNtpTime($channel->ReceivedInt);

// Show the current local date/time
$bLocalTime = true;
echo 'Current local date/time: ', $dt->GetAsRfc822($bLocalTime), "\n";

// Close the SSH channel.
try {
    $channel->Close($maxWaitMs);

    // 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.
    $tunnel->SshNewChannel('time-a.nist.gov', 37, $useTls, $maxWaitMs, $channel);
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

// Review the LastErrorText to see that the connection was made via the SSH tunnel:
echo $tunnel->LastErrorText, "\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.
try {
    $channel->Close($maxWaitMs);

    // Finally, close the SSH tunnel.
    $tunnel->SshCloseTunnel();
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

echo "TCP SSH tunneling example completed.\n";