CloudConnexa: How to enable DCO on a Linux connector

This article shows you how to install and turn on the DCO kernel module for a CloudConnexa Linux connector.

The DCO Kernel module allows OpenVPN to offload the data channel encryption and decryption to the Linux kernel. Thus, it can exploit any Linux low-level API while avoiding expensive and slow payload transfers between the kernel and user spaces. This enhances the OpenVPN tunnel's overall performance.

Install the DCO kernel module

1. Connect to your Linux connector console and run this command with root privileges to install the DCO kernel module (Ubuntu):

   sudo apt install openvpn-dco-dkms

   • The DCO package installs with other necessary packages.

Enable DCO for your connector's OpenVPN tunnel

1. Check the config name of the connector Linux machine:

   sudo openvpn3 sessions-list

   • The output displays the config name, similar to below. Note: Disregard the other lines of output. You only need the config name.

     Config name: CloudConnexa

2. Run these commands, one at a time, to disconnect your OpenVPN session and create a new one with DCO turned on:

   sudo openvpn3 session-manage -c <config name from last step> --disconnect
   sudo openvpn3 config-manage --show --config <config name from last step> --dco true
   sudo openvpn3 session-start -c <config name from last step> --dco true

   • DCO should now be turned on.
3. Verify your changes:
   sudo openvpn3 sessions-list
   • The output should include the following:

     Device: tun (DCO)
     Status: Connection, Client connected