Lua

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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Lua

local chilkat = require("chilkat")

-- 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.

local sshJump = chilkat.Ssh.new()

-- Connect and authenticate to the first SSH server (the jump host).
local sshPort = 22
local success = sshJump:connect("jump.example.com", sshPort)
if not success then
    print(sshJump.last_error_text)
    return
end

-- 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.
local password = "mySshPassword"

success = sshJump:authenticate_pw("jumpUser", password)
if not success then
    print(sshJump.last_error_text)
    return
end

-- Connect to the target SSH server through the jump host.
local sshTarget = chilkat.Ssh.new()
success = sshTarget:connect_through_ssh(sshJump, "target.example.com", sshPort)
if not success then
    print(sshTarget.last_error_text)
    return
end

-- Authenticate to the target server (separate credentials).
success = sshTarget:authenticate_pw("targetUser", password)
if not success then
    print(sshTarget.last_error_text)
    return
end

print("Connected to the target through the jump host.")

sshTarget:disconnect()
sshJump:disconnect()