PHP Extension

Connect to an SSH Server Through Another (Jump Host)

Demonstrates the Chilkat Ssh.ConnectThroughSsh method, which connects to a second SSH server through an already connected and authenticated Ssh object. The first argument is the first (jump-host) Ssh object, and the second and third are the destination hostname and port.

Background: This is SSH chaining through a "jump host" (bastion): the application connects to a reachable gateway, then tunnels onward to a target that is only accessible from inside the network. Each hop is authenticated separately with its own credentials. The result is a normal Ssh object for the target that happens to be routed through the first connection.

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PHP Extension

<?php

include("chilkat.php");

$success = false;

//  Demonstrates the Ssh.ConnectThroughSsh method, which connects to a second SSH server through
//  an already connected and authenticated Ssh object (a jump host).  The 1st argument is the
//  first Ssh object, and the 2nd and 3rd are the destination hostname and port.

$sshJump = new CkSsh();

//  Connect and authenticate to the first SSH server (the jump host).
$sshPort = 22;
$success = $sshJump->Connect('jump.example.com',$sshPort);
if ($success == false) {
    print $sshJump->lastErrorText() . "\n";
    exit;
}

//  Normally you would not hard-code the password in source.  You should instead obtain it
//  from an interactive prompt, environment variable, or a secrets vault.
$password = 'mySshPassword';

$success = $sshJump->AuthenticatePw('jumpUser',$password);
if ($success == false) {
    print $sshJump->lastErrorText() . "\n";
    exit;
}

//  Connect to the target SSH server through the jump host.
$sshTarget = new CkSsh();
$success = $sshTarget->ConnectThroughSsh($sshJump,'target.example.com',$sshPort);
if ($success == false) {
    print $sshTarget->lastErrorText() . "\n";
    exit;
}

//  Authenticate to the target server (separate credentials).
$success = $sshTarget->AuthenticatePw('targetUser',$password);
if ($success == false) {
    print $sshTarget->lastErrorText() . "\n";
    exit;
}

print 'Connected to the target through the jump host.' . "\n";

$sshTarget->Disconnect();
$sshJump->Disconnect();

?>