How to use the command 'vpnd' (with examples)

The ‘vpnd’ command is used to listen for incoming VPN (Virtual Private Network) connections. It is a daemon that runs in the background and handles VPN connections. It should not be invoked manually and is typically started automatically when needed.

Use case 1: Start the daemon

Code:

vpnd

Motivation: Starting the ‘vpnd’ daemon without any arguments will initiate the daemon, allowing it to listen for incoming VPN connections. This is the basic usage of the command to start the VPN daemon.

Example output: The ‘vpnd’ daemon will start running in the background and begin listening for incoming VPN connections.

Use case 2: Run the daemon in the foreground

Code:

vpnd -x

Motivation: Running the ‘vpnd’ daemon in the foreground allows you to see the output of the daemon directly on the terminal. This can be useful for debugging or monitoring purposes.

Example output: The ‘vpnd’ daemon will run in the foreground, and any output or logs will be displayed directly on the terminal.

Use case 3: Run the daemon in the foreground and print logs to the terminal

Code:

vpnd -d

Motivation: By running the ‘vpnd’ daemon in the foreground and enabling log printing, you can monitor the logs in real-time. This is particularly helpful for identifying any issues or errors that may occur during the operation of the VPN daemon.

Example output: The ‘vpnd’ daemon will run in the foreground, and detailed logs will be printed to the terminal in real-time.

Use case 4: Run the daemon in the foreground, print logs to the terminal, and quit after validating arguments

Code:

vpnd -n

Motivation: This use case is similar to the previous one, but with the additional argument ‘-n’ which allows the daemon to quit after validating arguments. This can be useful if you only need to check if the arguments provided to the daemon are valid without actually running it.

Example output: The ‘vpnd’ daemon will run in the foreground, print detailed logs to the terminal, validate the arguments, and then exit. The logs printed will contain information about the argument validation process.

Use case 5: Print usage summary and exit

Code:

vpnd -h

Motivation: Printing the usage summary and exiting is helpful when you want to quickly check the available options and arguments for the ‘vpnd’ command. This provides a concise overview of how to use the command.

Example output: The ‘vpnd’ command will print a summary of its usage options and available arguments, and then exit.

Use case 6: Run the daemon for a specific server configuration

Code:

vpnd -i server_id

Motivation: The ‘-i’ argument allows you to specify a specific server configuration for the ‘vpnd’ daemon to use. This can be beneficial if you have multiple server configurations and want to run the daemon using a particular one.

Example output: The ‘vpnd’ daemon will run using the server configuration specified by ‘server_id’. The output will show logs specific to the chosen server configuration.

Conclusion

The ‘vpnd’ command provides several options for running and monitoring the VPN daemon. From starting the daemon to specifying server configurations and printing logs, these use cases cover different scenarios for utilizing the ‘vpnd’ command effectively.