Lua

FTP over Implicit TLS (Ssl, AuthSsl, AutoFix)

Demonstrates the SSL/TLS connection-mode properties Ssl, AuthSsl, and AutoFix. Setting Ssl true selects implicit FTPS, in which TLS begins immediately after the TCP connection on port 990.

Background: FTP has two ways to add TLS: implicit (this example) starts encrypted from the first byte on a dedicated port, 990; explicit (via AuthTls) connects in the clear on port 21 and issues AUTH TLS to upgrade. Explicit is the modern standard; implicit persists mainly for legacy servers. AuthSsl is an obsolete AUTH SSL variant to avoid. AutoFix, on by default, infers the mode from the port — disable it when you set these properties explicitly so it does not override your choice.

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Lua

local chilkat = require("chilkat")

local ftp = chilkat.Ftp2.new()

ftp.hostname = "ftp.example.com"
ftp.username = "myFtpLogin"

-- 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.
ftp.password = "myPassword"

-- Ssl = true selects IMPLICIT FTPS: TLS begins immediately after the TCP connection, before
-- the greeting.  Port 990 is conventional for implicit FTPS.  Ssl takes priority over AuthTls
-- and AuthSsl.
ftp.ssl = true
ftp.port = 990

-- AuthSsl selects the legacy AUTH SSL command and is very uncommon -- use AuthTls (explicit
-- FTPS) for modern servers instead.  Left false here.
ftp.auth_ssl = false

-- AutoFix (default true) automatically adjusts Ssl/AuthTls/AuthSsl based solely on the Port
-- (21 or 990).  Disable it when setting these properties explicitly, as here.
ftp.auto_fix = false

local success = ftp:connect()
if not success then
    print(ftp.last_error_text)
    return
end

print("Connected using implicit FTPS.")

success = ftp:disconnect()
if not success then
    print(ftp.last_error_text)
    return
end