Port Forwarding

Overview

Port forwarding, or “tunneling,” is a method of moving insecure internet traffic though a secure shell between computers. On LinGA this is sometimes done to access web interfaces for applications and hardware on the clusters that is otherwise unreachable.

Sections

Connecting
Usage
Example

Related

Port Forwarding for Linux and Apple computers


Connecting

On Windows computers, port forwarding is added to a normal ssh session with PuTTY.

  1. Specify a remote computer to connect to, usually one of LinGA’s clusters.1-template
  2. In the left side-bar, navigate to Connection > SSH > Tunnels and specify
    • remote_port to bind
    • destination (local computer = localhost)
    • local_port to connect to


    2-template

  3. Click Add, to add the specified port. You can add multiple ports if required.
  4. Return to the Session page in the left side-bar to save the settings if you will need to do this again
  5. ClickĀ Open to open the connection and log in.

 

Once logged in, the port specified is connected to your local machine as long as the connection is open. Do not close the connection window until you are finished using the port.


Usage

Once a port is forwarded from a remote host to your computer, you can access the port as your own. Typically this means navigating to localhost:{local_port} in a web browser and using a web application assigned to that port.

 


Example: RStudio

Note: The following section references RubySky, which has since been merged with SCC. To use RStudio, replace “rubysky.bumc.bu.edu with “scc4.bu.edu” in the following instructions.

RStudio is installed on the RubySky Login Node. This particular application uses a web-interface on port 8787. Due to cluster-wide security requirements, our clusters are not directly connected to the internet and this port is inaccessible. To access this web-interface, you must securely ‘tunnel’ the traffic from the RubySky to your machine.

 

  1. Use PuTTY to setup a connection to RubySky.1-rs
  2. Specify port forwarding in Connection > SSH > Tunnels in the left side-bar as follows:1-rs (2)
  3. Click Add to add the port to the Forwarded Ports list.2.5-rs
  4. Click Open to open the connection and log in.
      Closing the putty window will terminate the session and disconnect the port. 

  5. Open a web-browser and navigate to “localhost:8787″.

This example forwards port 8787 from Rubysky to localhost:8787.
For other applications, use specified port.

 

4-rs