Visual Basic 6.0 Requires Chilkat v11.0.0+

SSH Tunnel Inside another SSH Tunnel

See more SSH Tunnel Examples

Demonstrates how to create a TCP/IP socket connection through an SSH tunnel that is dynamic port forwarded through another SSH tunnel. Visual Basic 6.0

Dim success As Long
success = 0

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

Dim tunnel As New ChilkatSshTunnel

Dim sshHostname As String
sshHostname = "www.ssh-serverA.com"
Dim sshPort As Long
sshPort = 22

'  Connect to an SSH server and establish the SSH tunnel:
success = tunnel.Connect(sshHostname,sshPort)
If (success = 0) Then
    Debug.Print tunnel.LastErrorText
    Exit Sub
End If

'  Authenticate with the SSH server via a login/password
'  or with a public key.  
'  This example demonstrates SSH password authentication.
success = tunnel.AuthenticatePw("mySshLogin","mySshPassword")
If (success = 0) Then
    Debug.Print tunnel.LastErrorText
    Exit Sub
End If

'  Indicate that the background SSH tunnel thread will behave as a SOCKS proxy server
'  with dynamic port forwarding:
tunnel.DynamicPortForwarding = 1

'  We may optionally require that connecting clients authenticate with our SOCKS proxy server.
'  To do this, set an inbound username/password.  Any connecting clients would be required to 
'  use SOCKS5 with the correct username/password.
'  If no inbound username/password is set, then our SOCKS proxy server will accept both
'  SOCKS4 and SOCKS5 unauthenticated connections.

tunnel.InboundSocksUsername = "chilkat123"
tunnel.InboundSocksPassword = "password123"

'  Start the listen/accept thread to begin accepting SOCKS proxy client connections.
'  Listen on port 1080.
success = tunnel.BeginAccepting(1080)
If (success = 0) Then
    Debug.Print tunnel.LastErrorText
    Exit Sub
End If

'  Now that a background thread is running a SOCKS proxy server that forwards connections
'  through an SSH tunnel, it is possible to use any Chilkat implemented protocol that is SOCKS capable,
'  such as HTTP, POP3, SMTP, IMAP, FTP, Socket, etc.  The protocol may use SSL/TLS because the SSL/TLS
'  will be passed through the SSH tunnel to the end-destination.  Also, any number of simultaneous
'  connections may be routed through the SSH tunnel.

Dim tunnelB As New ChilkatSocket

'  Indicate that the socket object is to use our portable SOCKS proxy/SSH tunnel running in our background thread.
tunnelB.SocksHostname = "localhost"
tunnelB.SocksPort = 1080
tunnelB.SocksVersion = 5
tunnelB.SocksUsername = "chilkat123"
tunnelB.SocksPassword = "password123"

'  Open a new SSH tunnel through the existing tunnel (via what we treat as a SOCKS5 proxy,
'  but it is actually a dynamic port-forwarded SSH tunnel).
success = tunnelB.SshOpenTunnel("www.ssh-serverB.com",22)
If (success = 0) Then
    Debug.Print tunnelB.LastErrorText
    Exit Sub
End If

'  Authenticate with ssh-serverB.com
success = tunnelB.SshAuthenticatePw("uname","pwd")
If (success = 0) Then
    Debug.Print tunnelB.LastErrorText
    Exit Sub
End If

'  OK, the SSH tunnel (within a tunnel) is setup.  Now open a channel within the tunnel.
'  Once the channel is obtained, the Socket API may
'  be used exactly the same as usual, except all communications
'  are sent through the channel in the SSH tunnel.
'  Any number of channels may be created from the same SSH tunnel.
'  Multiple channels may coexist at the same time.

'  Connect to an NIST time server and read the current date/time
Dim channel As New ChilkatSocket
Dim maxWaitMs As Long
maxWaitMs = 4000
Dim useTls As Long
useTls = 0
success = tunnelB.SshNewChannel("time-c.nist.gov",37,useTls,maxWaitMs,channel)
If (success = 0) Then
    Debug.Print tunnelB.LastErrorText
    Exit Sub
End If

'  The time server will send a big-endian 32-bit integer representing
'  the number of seconds since since 00:00 (midnight) 1 January 1900 GMT.
'  The ReceiveInt32 method will receive a 4-byte integer, but returns
'  1 or 0 to indicate success.  If successful, the integer
'  is obtained via the ReceivedInt property.
Dim bigEndian As Long
bigEndian = 1
success = channel.ReceiveInt32(bigEndian)
If (success = 0) Then
    Debug.Print channel.LastErrorText
    Exit Sub
End If

Dim dt As New CkDateTime
success = dt.SetFromNtpTime(channel.ReceivedInt)

'  Show the current local date/time
Dim bLocalTime As Long
bLocalTime = 1
Debug.Print "Current local date/time: " & dt.GetAsRfc822(bLocalTime)

'  Close the SSH channel.
success = channel.Close(maxWaitMs)
If (success = 0) Then
    Debug.Print channel.LastErrorText
    Exit Sub
End If

'  Stop the background listen/accept thread:
Dim waitForThreadExit As Long
waitForThreadExit = 1
success = tunnel.StopAccepting(waitForThreadExit)
If (success = 0) Then
    Debug.Print tunnel.LastErrorText
    Exit Sub
End If

'  Close the SSH tunnel (would also kick any remaining connected clients).
success = tunnel.CloseTunnel(waitForThreadExit)
If (success = 0) Then
    Debug.Print tunnel.LastErrorText
    Exit Sub
End If