How to use ProxyCommand or SSH forwarding

Question

How to use ProxyCommand or SSH forwarding

Mohamed 5

https://learn.microsoft.com/en-us/azure/active-directory/devices/howto-vm-sign-in-azure-ad-linux

The above link describes the "az ssh vm", but not in a detailed manner. I want to use ProxyCommand or SSH forwarding in "az ssh vm".

Michell Easmus 0

ProxyCommand and SSH forwarding are both useful techniques for establishing secure connections and accessing remote systems through an intermediate server. Here's an explanation of how to use them:

ProxyCommand:

ProxyCommand allows you to establish an SSH connection through an intermediate server to reach the final destination. It can be helpful when the intermediate server allows SSH access but the final destination is not directly accessible.
The ProxyCommand option is specified in your SSH configuration file (~/.ssh/config) or directly on the command line.
- Here's an example of how to use ProxyCommand in your SSH configuration file:

      perl
      Copy code
      Host final_destination
          ProxyCommand ssh -q -W %h:%p intermediate_server
      ```

        
      In this example, replace **`final_destination`** with the hostname or IP address of the final destination, and **`intermediate_server`** with the hostname or IP address of the intermediate server.

   - When you establish an SSH connection to **`final_destination`**, SSH will automatically connect to **`intermediate_server`** first and then establish a second connection to **`final_destination`**.

1. SSH Forwarding:

- SSH forwarding allows you to securely forward network connections from your local machine to a remote server or vice versa.

   - There are two types of SSH forwarding: local forwarding and remote forwarding.

      - Local Forwarding:

         - Local forwarding allows you to forward connections from your local machine to a remote server.  
                  Use the **`-L`** option to specify local forwarding. The syntax is as follows:

                  ssh -L local_port:destination_host:destination_port intermediate_server  
                  Replace **`local_port`** with the port number on your local machine that you want to use for forwarding, **`destination_host`** with the hostname or IP address of the destination server, **`destination_port`** with the port number on the destination server you want to connect to, and **`intermediate_server`** with the hostname or IP address of the intermediate server.

      - Remote Forwarding:

            - Remote forwarding allows you to forward connections from a remote server to your local machine.

         - Use the **`-R`** option to specify remote forwarding. The syntax is as follows:  
                    
                  `ssh -R remote_port:destination_host:destination_port intermediate_server
                  `Replace **`remote_port`** with the port number on the remote server that you want to use for forwarding, **`destination_host`** with the hostname or IP address of your local machine, **`destination_port`** with the port number on your local machine you want to connect to, and **`intermediate_server`** with the hostname or IP address of the intermediate server.

Remember to replace the placeholders (**`final_destination`**, **`intermediate_server`**, **`local_port`**, **`destination_host`**, **`destination_port`**, **`remote_port`**) with the appropriate values specific to your setup.

By using ProxyCommand and SSH forwarding, you can establish secure connections and access remote systems through intermediate servers, enabling you to navigate network restrictions and securely manage your infrastructure.

Mohamed 5 Reputation points

2023-05-19T07:06:20.83+00:00

@Michell Easmus But I need to use it in "az ssh vm" in azure cloud shell.

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Mohamed 5 Reputation points

2023-05-19T07:06:20.83+00:00

@Michell Easmus But I need to use it in "az ssh vm" in azure cloud shell.

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How to use ProxyCommand or SSH forwarding

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