How To Install OpenConnect VPN on Ubuntu 24.04 LTS

In today’s digital age, online security and privacy have become paramount concerns for individuals and businesses alike. Virtual Private Networks (VPNs) have emerged as a reliable solution to protect your internet traffic and safeguard sensitive information from prying eyes. OpenConnect VPN is a popular open-source VPN protocol that offers robust security features and seamless compatibility with Ubuntu 24.04. In this comprehensive guide, we will walk you through the step-by-step process of installing and configuring OpenConnect VPN on your Ubuntu 24.04 system.

Prerequisites

Before we dive into the installation process, ensure that your Ubuntu 24.04 system meets the following requirements:

• A fresh installation of Ubuntu 24.04 with the latest updates and patches.
• Sudo privileges to execute administrative commands.

To update your system packages, open the terminal and run the following command:

sudo apt update && sudo apt upgrade

Step 1: Install OpenConnect VPN Server

The first step is to install the OpenConnect VPN server on your Ubuntu 24.04 machine. Open the terminal and execute the following command:

sudo apt install ocserv

This command will download and install the necessary packages for OpenConnect VPN. Once the installation is complete, you can verify the service status by running:

systemctl status ocserv

If the installation was successful, you should see the OpenConnect VPN service running.

Step 2: Configure Firewall Settings

To ensure that OpenConnect VPN functions properly, you need to configure your firewall settings to allow incoming connections on the necessary ports. Ubuntu 24.04 comes with the Uncomplicated Firewall (UFW) by default. Open the required ports by executing the following command:

sudo ufw allow 80,443/tcp

This command opens ports 80 and 443, which are used for HTTP and HTTPS traffic, respectively.

Step 3: Configure OpenConnect Server

With the OpenConnect VPN server installed and the firewall configured, it’s time to configure the server settings. The main configuration file for OpenConnect is located at /etc/ocserv/ocserv.conf. Open this file using a text editor with sudo privileges:

sudo nano /etc/ocserv/ocserv.conf

Inside the configuration file, you’ll find various settings that you can customize according to your requirements. Some of the essential settings include:

• Authentication method
• DNS settings
• Routing configuration

For example, to set up authentication using a password file, locate the following line:

auth = "plain[passwd=/etc/ocserv/ocpasswd]"

This line specifies that the server will use a plain-text password file located at /etc/ocserv/ocpasswd for user authentication.

After making the necessary changes, save the file and exit the text editor. Then, restart the OpenConnect VPN service to apply the new configuration:

sudo systemctl restart ocserv

Step 4: Create VPN User Accounts

To access the OpenConnect VPN server, you need to create user accounts. OpenConnect provides a utility called ocpasswd for managing user accounts. To create a new user account, run the following command:

sudo ocpasswd -c /etc/ocserv/ocpasswd username

Replace username with the desired username for the VPN account. You will be prompted to enter and confirm a password for the user.

Step 5: Enable IP Forwarding and Masquerading

To enable the OpenConnect VPN server to route traffic correctly, you need to enable IP forwarding and configure IP masquerading. Start by editing the sysctl configuration file:

sudo nano /etc/sysctl.conf

Locate the following line and uncomment it (remove the ‘#’ at the beginning) or add it if it doesn’t exist:

net.ipv4.ip_forward=1

Save the file and exit the text editor. Apply the changes by running:

sudo sysctl -p

Next, configure IP masquerading using iptables. Execute the following commands:

sudo iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
sudo iptables -A FORWARD -i eth0 -o vpns+ -m state --state RELATED,ESTABLISHED -j ACCEPT
sudo iptables -A FORWARD -i vpns+ -o eth0 -j ACCEPT

Replace eth0 with the name of your network interface if it differs.

Step 6: Install OpenConnect VPN Client on Ubuntu Desktop

To connect to the OpenConnect VPN server from an Ubuntu desktop, you need to install the OpenConnect VPN client. Open the terminal and run the following command:

sudo apt install openconnect

Once the installation is complete, you can connect to the VPN server using the command line. Use the following command:

sudo openconnect -b vpn.example.com

Replace vpn.example.com with the domain name or IP address of your OpenConnect VPN server. You will be prompted to enter your VPN username and password.

Step 7: Troubleshooting Common Issues

If you encounter any issues while setting up or connecting to the OpenConnect VPN server, here are a few troubleshooting tips:

• Double-check your network settings and ensure that the firewall is configured correctly.
• Verify that the OpenConnect VPN service is running by using the systemctl status ocserv command.
• Check the OpenConnect VPN server logs for any error messages. The logs are typically located in /var/log/ocserv/.
• Ensure that you are using the correct VPN credentials when connecting from the client.

If the issue persists, consult the OpenConnect VPN documentation or seek assistance from the OpenConnect community forums.

Step 8: Advanced Configuration Options

OpenConnect VPN offers various advanced configuration options to customize your VPN setup further. Some of these options include:

• Setting up custom scripts for additional functionality.
• Optimizing network performance by adjusting MTU and TLS settings.
• Configuring a systemd service to automatically start the OpenConnect VPN server on system boot.

To explore these advanced options, refer to the OpenConnect VPN documentation and configuration examples available online.

Congratulations! You have successfully installed OpenConnect. Thanks for using this tutorial for installing the OpenConnect on the Ubuntu 24.04 LTS system. For additional help or useful information, we recommend you check the official OpenConnect website.