How to use the command vpnc (with examples)

The vpnc command is a VPN client that is used to connect to the Cisco 3000 VPN Concentrator. It allows users to establish a secure connection to a remote network using the VPN protocol. The command requires root privileges to run, hence the use of sudo in the examples.

Use case 1: Connect with a defined configuration file

Code:

$ sudo vpnc config_file

Motivation: This use case is useful when you want to connect to a VPN using a specific configuration file. By providing the configuration file as an argument, the vpnc command can automatically establish the connection with the specified settings.

Explanation:

• sudo: This command is used to run vpnc with root privileges. This is necessary because creating a VPN connection requires administrative access.
• vpnc: The vpnc command itself, which is used to create a VPN connection.
• config_file: The name and path of the configuration file that describes the VPN connection settings.

Example output:

VPNC started in background (pid: 1234)...

Use case 2: Terminate the previously created connection

Code:

$ sudo vpnc-disconnect

Motivation: This use case allows the user to easily terminate an active VPN connection. It is useful when you no longer need to access the remote network and want to disconnect from the VPN server.

Explanation:

• sudo: As before, this is used to run the vpnc-disconnect command with root privileges.
• vpnc-disconnect: This is the command used to terminate the VPN connection.

Example output:

Disconnecting VPN...
VPN disconnected successfully.

Conclusion:

The vpnc command is a versatile tool for connecting to VPNs using the Cisco 3000 VPN Concentrator. It provides a straightforward way to establish a VPN connection using a defined configuration file and also allows for easy termination of the connection when it is no longer needed. By using these examples, you can efficiently manage your VPN connections with the vpnc command.