Lua Requires Chilkat v11.0.0+

POP3 SSH Tunneling (Port Forwarding)

Demonstrates how to connect to a POP3 server through an SSH tunnel. Reads a POP3 mailbox and display the FROM and SUBJECT header fields of each email. Lua

local chilkat = require("chilkat")

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

-- The mailman object is used for receiving (POP3)
-- and sending (SMTP) email.
local mailman = chilkat.MailMan.new()

-- The SSH hostname may be a hostname or an
-- IP address, such as "192.168.1.108".
-- The port is typically 22 (the standard port for SSH).
local sshHostname = "sftp.example.com"
local sshPort = 22

-- Connect to an SSH server and establish the SSH tunnel:
local success = mailman:ssh_open_tunnel(sshHostname, sshPort)
if not success then
    print(mailman.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.
-- Note: This is not authenticating with the POP3 server, it is
-- for authenticating with the SSH server, which is separate.
success = mailman:ssh_authenticate_pw("ssh_login", "ssh_password")
if not success then
    print(mailman.last_error_text)
    return
end

-- OK, the SSH tunnel is setup.  The mailman may
-- be used exactly the same as usual, except all communications
-- are now sent through the SSH tunnel.

-- The SSH tunnel may be kept open for any number of
-- POP3 connections.

-- Set the POP3 server's hostname
mailman.mail_host = "mail.my-pop3-server.com"

-- Set the POP3 settings for your POP3 server:
mailman.pop_username = "pop3_login"
mailman.pop_password = "pop3_password"
mailman.mail_port = 995
mailman.pop_ssl = true

-- Connect to the POP3 server through the already-established SSH tunnel:
success = mailman:pop3_begin_session()
if not success then
    print(mailman.last_error_text)
    return
end

-- A visual inspection of the LastErrorText after
-- a successful POP3 connection will confirm the SSH tunneling.
-- Note: If the POP3 connection uses SSL/TLS, then the SSL/TLS
-- secure channel will be wrapped within the SSH tunnel.
print(mailman.last_error_text)

-- How many messages are in the POP3 inbox?
local numToDownload = mailman:get_mailbox_count()
if numToDownload > 5 then
    numToDownload = 5
end

if numToDownload == 0 then
    print("No messages in the POP3 inbox.")
    return
end

-- Download a max of 5 messages
local email = chilkat.Email.new()
for i = 1, numToDownload do
    success = mailman:fetch_one(false, 0, i, email)
    if not success then
        print(mailman.last_error_text)
        return
    end

    print(email.from)
    print(email.subject)
    print("----")
end

-- Close the connection with the POP3 server, leaving the SSH tunnel open for subsequent POP3 connections.
success = mailman:pop3_end_session()
if not success then
    print(mailman.last_error_text)
    return
end

-- Try connecting to a different POP3 server through the same aleady setup SSH tunnel:
-- Set the POP3 server's hostname
mailman.mail_host = "mail.my-pop3-server2.com"

-- Set the POP3 settings for your POP3 server:
mailman.pop_username = "pop3_login2"
mailman.pop_password = "pop3_password2"
mailman.mail_port = 110
mailman.pop_ssl = false

success = mailman:pop3_begin_session()
if not success then
    print(mailman.last_error_text)
    return
end

-- Review the LastErrorText to see that the connection was made via the SSH tunnel:
print(mailman.last_error_text)

success = mailman:pop3_end_session()
if not success then
    print(mailman.last_error_text)
    return
end

-- Close the SSH tunnel.
success = mailman:ssh_close_tunnel()
if not success then
    print(mailman.last_error_text)
    return
end