.NET Core C#

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. .NET Core C#

bool success = false;

// 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.
Chilkat.MailMan mailman = new Chilkat.MailMan();

// 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).
string sshHostname = "sftp.example.com";
int sshPort = 22;

// Connect to an SSH server and establish the SSH tunnel:
success = mailman.SshOpenTunnel(sshHostname,sshPort);
if (success == false) {
    Debug.WriteLine(mailman.LastErrorText);
    return;
}

// 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 == false) {
    Debug.WriteLine(mailman.LastErrorText);
    return;
}

// 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.MailHost = "mail.my-pop3-server.com";

// Set the POP3 settings for your POP3 server:
mailman.PopUsername = "pop3_login";
mailman.PopPassword = "pop3_password";
mailman.MailPort = 995;
mailman.PopSsl = true;

// Connect to the POP3 server through the already-established SSH tunnel:
success = mailman.Pop3BeginSession();
if (success == false) {
    Debug.WriteLine(mailman.LastErrorText);
    return;
}

// 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.
Debug.WriteLine(mailman.LastErrorText);

// How many messages are in the POP3 inbox?
int numToDownload = mailman.GetMailboxCount();
if (numToDownload > 5) {
    numToDownload = 5;
}

if (numToDownload == 0) {
    Debug.WriteLine("No messages in the POP3 inbox.");
    return;
}

// Download a max of 5 messages
int i;
Chilkat.Email email = new Chilkat.Email();
for (i = 1; i <= numToDownload; i++) {
    success = mailman.FetchOne(false,0,i,email);
    if (success == false) {
        Debug.WriteLine(mailman.LastErrorText);
        return;
    }

    Debug.WriteLine(email.From);
    Debug.WriteLine(email.Subject);
    Debug.WriteLine("----");
}

// Close the connection with the POP3 server, leaving the SSH tunnel open for subsequent POP3 connections.
success = mailman.Pop3EndSession();
if (success == false) {
    Debug.WriteLine(mailman.LastErrorText);
    return;
}

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

// Set the POP3 settings for your POP3 server:
mailman.PopUsername = "pop3_login2";
mailman.PopPassword = "pop3_password2";
mailman.MailPort = 110;
mailman.PopSsl = false;

success = mailman.Pop3BeginSession();
if (success == false) {
    Debug.WriteLine(mailman.LastErrorText);
    return;
}

// Review the LastErrorText to see that the connection was made via the SSH tunnel:
Debug.WriteLine(mailman.LastErrorText);

success = mailman.Pop3EndSession();
if (success == false) {
    Debug.WriteLine(mailman.LastErrorText);
    return;
}

// Close the SSH tunnel.
success = mailman.SshCloseTunnel();
if (success == false) {
    Debug.WriteLine(mailman.LastErrorText);
    return;
}