(Perl) 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.

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.

# The mailman object is used for receiving (POP3) 
# and sending (SMTP) email.
$mailman = chilkat::CkMailMan->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).
$sshHostname = "www.my-ssh-server.com";
$sshPort = 22;

# Connect to an SSH server and establish the SSH tunnel:
$success = $mailman->SshOpenTunnel($sshHostname,$sshPort);
if ($success != 1) {
    print $mailman->lastErrorText() . "\r\n";
    exit;
}

# 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 = $mailman->SshAuthenticatePw("ssh_login","ssh_password");
if ($success != 1) {
    print $mailman->lastErrorText() . "\r\n";
    exit;
}

# 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->put_MailHost("mail.my-pop3-server.com");

# Set the POP3 settings for your POP3 server:
$mailman->put_PopUsername("pop3_login");
$mailman->put_PopPassword("pop3_password");
$mailman->put_MailPort(995);
$mailman->put_PopSsl(1);

# Connect to the POP3 server through the already-established SSH tunnel:
$success = $mailman->Pop3BeginSession();
if ($success != 1) {
    print $mailman->lastErrorText() . "\r\n";
    exit;
}

# 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->lastErrorText() . "\r\n";

# How many messages are in the POP3 inbox?
$numToDownload = $mailman->GetMailboxCount();
if ($numToDownload > 5) {
    $numToDownload = 5;
}

if ($numToDownload == 0) {
    exit;
}

# Download a max of 5 messages

for ($i = 1; $i <= $numToDownload; $i++) {
    # email is a Email
    $email = $mailman->FetchByMsgnum($i);
    if ($mailman->get_LastMethodSuccess() == 0) {
        print $mailman->lastErrorText() . "\r\n";
        exit;
    }

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

}

# Close the connection with the POP3 server, leaving the SSH tunnel open for subsequent POP3 connections.
$success = $mailman->Pop3EndSession();
if ($success != 1) {
    print $mailman->lastErrorText() . "\r\n";
    exit;
}

# Try connecting to a different POP3 server through the same aleady setup SSH tunnel:
# Set the POP3 server's hostname
$mailman->put_MailHost("mail.my-pop3-server2.com");

# Set the POP3 settings for your POP3 server:
$mailman->put_PopUsername("pop3_login2");
$mailman->put_PopPassword("pop3_password2");
$mailman->put_MailPort(110);
$mailman->put_PopSsl(0);

$success = $mailman->Pop3BeginSession();
if ($success != 1) {
    print $mailman->lastErrorText() . "\r\n";
    exit;
}

# Review the LastErrorText to see that the connection was made via the SSH tunnel:
print $mailman->lastErrorText() . "\r\n";

$success = $mailman->Pop3EndSession();
if ($success != 1) {
    print $mailman->lastErrorText() . "\r\n";
    exit;
}

# Close the SSH tunnel.
$success = $mailman->SshCloseTunnel();
if ($success != 1) {
    print $mailman->lastErrorText() . "\r\n";
    exit;
}