Perl

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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use strict;
use warnings;
use Chilkat2;

# 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.

my $sshJump = Chilkat2::Ssh->new;

# Connect and authenticate to the first SSH server (the jump host).
my $sshPort = 22;
my $success = $sshJump->Connect('jump.example.com', $sshPort);
if (!$success) {
    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.
my $password = 'mySshPassword';

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

# Connect to the target SSH server through the jump host.
my $sshTarget = Chilkat2::Ssh->new;
$success = $sshTarget->ConnectThroughSsh($sshJump, 'target.example.com', $sshPort);
if (!$success) {
    print $sshTarget->LastErrorText, "\n";
    exit;
}

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

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

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