Lua

SSH Through a SOCKS Proxy

Demonstrates connecting to an SSH server through a SOCKS4 or SOCKS5 proxy. Set the SOCKS properties before calling Connect, and set SocksVersion to match the proxy server.

Background: SOCKS is a general-purpose TCP relay, so unlike an HTTP proxy it is designed from the start to carry arbitrary protocols — usually the smoother option for SSH. The version matters: SOCKS4 supports only a username with no password, while SOCKS5 supports full login/password authentication as well as IPv6 and remote DNS resolution. Note this is the inverse of dynamic port forwarding: here a SOCKS proxy is used to reach the SSH server, rather than SSH providing a SOCKS proxy.

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Lua

local chilkat = require("chilkat")

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

-- Demonstrates connecting to an SSH server through a SOCKS4 or SOCKS5 proxy.

local ssh = chilkat.Ssh.new()

-- Set the SOCKS proxy properties before connecting.  The hostname may be a domain name or an
-- IP address.
ssh.socks_hostname = "socks.example.com"
ssh.socks_port = 1080
ssh.socks_username = "mySocksLogin"
ssh.socks_password = "mySocksPassword"

-- Set the version to match the proxy server: 4 or 5.
-- Note: SOCKS4 supports only a username, with no password.  SOCKS5 supports full
-- login/password authentication.
ssh.socks_version = 5

local hostname = "ssh.example.com"
local port = 22
local success = ssh:connect(hostname, port)
if not success then
    print(ssh.last_error_text)
    return
end

print("Connected to the SSH server through the SOCKS proxy.")

-- 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 = ssh:authenticate_pw("mySshLogin", password)
if not success then
    print(ssh.last_error_text)
    return
end

-- ... use the SSH connection normally ...

ssh:disconnect()