(C#) TCP or TLS over Multiple Hop SSH to Remote Server

Demonstrates how to use the Chilkat Socket API to connect to a remote server (using TCP or TLS) tunneled through mulitple-hop SSH. The scheme looks like this:

Application => ServerSSH1 => ServerSSH2 => DestinationServer

The ConnectThroughSsh and UseSsh methods are added in Chilkat version 9.5.0.55 to accomplish this task.

Chilkat .NET Downloads Chilkat .NET Framework Chilkat for .NET Core

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

Chilkat.Ssh ssh1 = new Chilkat.Ssh();

// Connect directly to the 1st SSH server.
bool success = ssh1.Connect("serverssh1.com",22);
if (success != true) {
    Debug.WriteLine(ssh1.LastErrorText);
    return;
}

// Authenticate using login/password:
success = ssh1.AuthenticatePw("ssh1Login","ssh1Password");
if (success != true) {
    Debug.WriteLine(ssh1.LastErrorText);
    return;
}

// 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.
Chilkat.Ssh ssh2 = new Chilkat.Ssh();
success = ssh2.ConnectThroughSsh(ssh1,"serverssh2.com",22);
if (success != true) {
    Debug.WriteLine(ssh2.LastErrorText);
    return;
}

// Authenticate with ssh2...
success = ssh2.AuthenticatePw("ssh2Login","ssh2Password");
if (success != true) {
    Debug.WriteLine(ssh2.LastErrorText);
    return;
}

Chilkat.Socket socket = new Chilkat.Socket();

// Tell the socket object to connect to our destination server though the ssh2 tunnel (which itself is routed through ssh1).
// The connection looks like this:  ApplicationSocket(TLS) => ServerSSH1 => ServerSSH2 => DestinationServer
success = socket.UseSsh(ssh2);
if (success != true) {
    Debug.WriteLine(socket.LastErrorText);
    return;
}

// Connect using TLS to www.chilkatsoft.com
// We could also tunnel a bare TCP connection by specifying port 80 with useTls = false.
bool useTls = true;
int maxWaitMillisec = 20000;
success = socket.Connect("www.chilkatsoft.com",443,useTls,maxWaitMillisec);
if (success != true) {
    Debug.WriteLine(socket.LastErrorText);
    return;
}

// Once the multiple hop SSH tunneled connection is setup,  the socket programming
// is identical to the normal case where we have a direct connection.

// Tell the socket object that all text is to be sent in the utf-8 encoding,
// and the text received is assumed to be utf-8.
socket.StringCharset = "utf-8";

// Send an HTTP HEAD request:
success = socket.SendString("HEAD / HTTP/1.1\r\nHost: www.chilkatsoft.com\r\n\r\n");
if (success != true) {
    Debug.WriteLine(socket.LastErrorText);
    return;
}

// Wait a maximum of 4 seconds while no data is forthcoming:
socket.MaxReadIdleMs = 4000;

// Get the 1st response line, which should be "HTTP/1.1 200 OK"
string responseStatusLine = socket.ReceiveToCRLF();
if (socket.LastMethodSuccess != true) {
    Debug.WriteLine(socket.LastErrorText);
    return;
}

Debug.WriteLine("StatusLine: " + responseStatusLine);

// Now get the 1st line of the response header:
string responseHeaderLine = socket.ReceiveToCRLF();
if (socket.LastMethodSuccess != true) {
    Debug.WriteLine(socket.LastErrorText);
    return;
}

Debug.WriteLine("HeaderLine: " + responseHeaderLine);

// Now read the remainder of the response header by reading until a double CRLF is seen:
string remainderOfHeader = socket.ReceiveUntilMatch("\r\n\r\n");
if (socket.LastMethodSuccess != true) {
    Debug.WriteLine(socket.LastErrorText);
    return;
}

Debug.WriteLine("Remainder: " + remainderOfHeader);

// Close the connection with the server.  This closes the tunnel through ssh2.
// Wait a max of 20 seconds (20000 millsec)
success = socket.Close(20000);

// 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();