Lua Requires Chilkat v11.0.0+

SSH Tunnel Inside another SSH Tunnel

See more SSH Tunnel Examples

Demonstrates how to create a TCP/IP socket connection through an SSH tunnel that is dynamic port forwarded through another SSH tunnel. Lua

local chilkat = require("chilkat")

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

local tunnel = chilkat.SshTunnel.new()

local sshHostname = "www.ssh-serverA.com"
local sshPort = 22

-- Connect to an SSH server and establish the SSH tunnel:
local success = tunnel:connect(sshHostname, sshPort)
if not success then
    print(tunnel.last_error_text)
    return
end

-- Authenticate with the SSH server via a login/password
-- or with a public key.
-- This example demonstrates SSH password authentication.
success = tunnel:authenticate_pw("mySshLogin", "mySshPassword")
if not success then
    print(tunnel.last_error_text)
    return
end

-- Indicate that the background SSH tunnel thread will behave as a SOCKS proxy server
-- with dynamic port forwarding:
tunnel.dynamic_port_forwarding = true

-- We may optionally require that connecting clients authenticate with our SOCKS proxy server.
-- To do this, set an inbound username/password.  Any connecting clients would be required to
-- use SOCKS5 with the correct username/password.
-- If no inbound username/password is set, then our SOCKS proxy server will accept both
-- SOCKS4 and SOCKS5 unauthenticated connections.

tunnel.inbound_socks_username = "chilkat123"
tunnel.inbound_socks_password = "password123"

-- Start the listen/accept thread to begin accepting SOCKS proxy client connections.
-- Listen on port 1080.
success = tunnel:begin_accepting(1080)
if not success then
    print(tunnel.last_error_text)
    return
end

-- Now that a background thread is running a SOCKS proxy server that forwards connections
-- through an SSH tunnel, it is possible to use any Chilkat implemented protocol that is SOCKS capable,
-- such as HTTP, POP3, SMTP, IMAP, FTP, Socket, etc.  The protocol may use SSL/TLS because the SSL/TLS
-- will be passed through the SSH tunnel to the end-destination.  Also, any number of simultaneous
-- connections may be routed through the SSH tunnel.

local tunnelB = chilkat.Socket.new()

-- Indicate that the socket object is to use our portable SOCKS proxy/SSH tunnel running in our background thread.
tunnelB.socks_hostname = "localhost"
tunnelB.socks_port = 1080
tunnelB.socks_version = 5
tunnelB.socks_username = "chilkat123"
tunnelB.socks_password = "password123"

-- Open a new SSH tunnel through the existing tunnel (via what we treat as a SOCKS5 proxy,
-- but it is actually a dynamic port-forwarded SSH tunnel).
success = tunnelB:ssh_open_tunnel("www.ssh-serverB.com", 22)
if not success then
    print(tunnelB.last_error_text)
    return
end

-- Authenticate with ssh-serverB.com
success = tunnelB:ssh_authenticate_pw("uname", "pwd")
if not success then
    print(tunnelB.last_error_text)
    return
end

-- OK, the SSH tunnel (within a 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
local channel = chilkat.Socket.new()
local maxWaitMs = 4000
local useTls = false
success = tunnelB:ssh_new_channel("time-c.nist.gov", 37, useTls, maxWaitMs, channel)
if not success then
    print(tunnelB.last_error_text)
    return
end

-- 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.
local bigEndian = true
success = channel:receive_int32(bigEndian)
if not success then
    print(channel.last_error_text)
    return
end

local dt = chilkat.DateTime.new()
dt:set_from_ntp_time(channel.received_int)

-- Show the current local date/time
local bLocalTime = true
print("Current local date/time: " .. dt:get_as_rfc822(bLocalTime))

-- Close the SSH channel.
success = channel:close(maxWaitMs)
if not success then
    print(channel.last_error_text)
    return
end

-- Stop the background listen/accept thread:
local waitForThreadExit = true
success = tunnel:stop_accepting(waitForThreadExit)
if not success then
    print(tunnel.last_error_text)
    return
end

-- Close the SSH tunnel (would also kick any remaining connected clients).
success = tunnel:close_tunnel(waitForThreadExit)
if not success then
    print(tunnel.last_error_text)
    return
end