(Perl) 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 Perl Downloads Perl Module for Windows, MacOS, Linux, Alpine Linux, Solaris

use chilkat();

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

$ssh1 = chilkat::CkSsh->new();

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

# Authenticate using login/password:
$success = $ssh1->AuthenticatePw("ssh1Login","ssh1Password");
if ($success != 1) {
    print $ssh1->lastErrorText() . "\r\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 = chilkat::CkSsh->new();
$success = $ssh2->ConnectThroughSsh($ssh1,"serverssh2.com",22);
if ($success != 1) {
    print $ssh2->lastErrorText() . "\r\n";
    exit;
}

# Authenticate with ssh2...
$success = $ssh2->AuthenticatePw("ssh2Login","ssh2Password");
if ($success != 1) {
    print $ssh2->lastErrorText() . "\r\n";
    exit;
}

$mailman = chilkat::CkMailMan->new();

# 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 != 1) {
    print $mailman->lastErrorText() . "\r\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 != 1) {
    print $mailman->lastErrorText() . "\r\n";
    exit;
}

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

$i = 1;

while ($i <= $numMessages) {

    # email is a Email
    $email = $mailman->FetchByMsgnum($i);
    if ($mailman->get_LastMethodSuccess() != 1) {
        print $mailman->lastErrorText() . "\r\n";
        exit;
    }

    print $email->ck_from() . ": " . $email->subject() . "\n" . "\r\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();