(PHP Extension) POP3 over Multiple Hop SSH

Demonstrates how to read POP3 email (using TCP or TLS) tunneled through mulitple-hop SSH. The scheme looks like this:

Application => ServerSSH1 => ServerSSH2 => POP3Server

Chilkat PHP Downloads PHP Extension for Windows, Linux, MacOS, Alpine Linux, Solaris

<?php

// The version number (9_5_0) should match version of the Chilkat extension used, omitting the micro-version number.
// For example, if using Chilkat v9.5.0.48, then include as shown here:
include("chilkat_9_5_0.php");

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

$ssh1 = new CkSsh();

// Connect directly to the 1st SSH server.
$success = $ssh1->Connect('serverssh1.com',22);
if ($success != true) {
    print $ssh1->lastErrorText() . "\n";
    exit;
}

// Authenticate using login/password:
$success = $ssh1->AuthenticatePw('ssh1Login','ssh1Password');
if ($success != true) {
    print $ssh1->lastErrorText() . "\n";
    exit;
}

// Connect through the 1st SSH connection to reach a 2nd SSH server.
// Note: Any number of SSH connections may be simultaneously tunneled through a single
// existing SSH connection.
$ssh2 = new CkSsh();
$success = $ssh2->ConnectThroughSsh($ssh1,'serverssh2.com',22);
if ($success != true) {
    print $ssh2->lastErrorText() . "\n";
    exit;
}

// Authenticate with ssh2...
$success = $ssh2->AuthenticatePw('ssh2Login','ssh2Password');
if ($success != true) {
    print $ssh2->lastErrorText() . "\n";
    exit;
}

$mailman = new CkMailMan();

// Tell the mailman object to connect to the POP3 server though the ssh2 tunnel (which itself is routed through ssh1).
// The connection looks like this:  Application => ServerSSH1 => ServerSSH2 => POP3Server
$success = $mailman->UseSsh($ssh2);
if ($success != true) {
    print $mailman->lastErrorText() . "\n";
    exit;
}

// Set the POP3 server's hostname
$mailman->put_MailHost('pop.someMailServer.com');

// Set the POP3 login/password.
$mailman->put_PopUsername('myLogin');
$mailman->put_PopPassword('myPassword');

// Establish the POP3 connection through the ssh2 tunnel.
$success = $mailman->Pop3BeginSession();
if ($success != true) {
    print $mailman->lastErrorText() . "\n";
    exit;
}

// Get the number of messages in the mailbox.
$numMessages = $mailman->GetMailboxCount();

$i = 1;

while ($i <= $numMessages) {

    // email is a CkEmail
    $email = $mailman->FetchByMsgnum($i);
    if ($mailman->get_LastMethodSuccess() != true) {
        print $mailman->lastErrorText() . "\n";
        exit;
    }

    print $email->from() . ': ' . $email->subject() . '\n' . "\n";

    $i = $i + 1;
}

// Close the connection with the POP3 server.  (This closes the tunnel through ssh2)
// The connection with ssh2 is still alive, and may be used for more connections.
$success = $mailman->Pop3EndSession();

// Close the connection with ssh2.  (This closes the the tunnel through ssh1.)
// The connection with ssh1 is still alive, and may be used for more connections.

$ssh2->Disconnect();

$ssh1->Disconnect();

?>