Openvpn

OpenVPN uses SSL/TLS to establish secure, encrypted tunnels. It supports both site-to-site and remote access setups, offering strong security through certificate-based authentication.

By deploying OpenVPN on your router, you can create secure connections to access your local network remotely or interconnect multiple networks across different locations.

Example of setting up OpenVPN Client

1. Upload Configuration Files

1.1 Client Settings

Navigate to the router menu: SYSTEM > Terminal. Enter the username root and log in with your configured password.

wg genkey | tee privatekey | wg pubkey > publickey
cat privatekey
cat publickey

Using the command above, you can generate and view the router’s private and public keys, then save their information in a notepad.

1.2 Client Settings

Here, WireGuard for macOS is used for demonstration.

Open WireGuard, click the + sign in the lower left corner, select Add Empty Tunnel, and the public and private keys for macOS WireGuard will be automatically generated, as shown in the following figure.

2. Add the WireGuard interface

Navigate to the router menu bar NETWORK > Interface, click the Add new interface button at the lower left corner, enter a custom interface name such as wg0, select the WireGuard protocol, and click the Save & Apply buttons. Then it will automatically jump to the configuration page of the wg0 interface.

3. Set up the Wireguard interface

3.1 General Setup

Private key: Paste the private key generated in Step 1
Listening port: Use custom high-bit ports (such as 51820), avoiding common ports.
IP address: Configure a dedicated VPN network segment (such as 10.0.0.1/24), ensuring it does not conflict with the existing local network.

3.2 Peers Setup

Public Key: Client’s public key (not the server’s public key)

Allowed IPs: The IP address assigned to the client (such as 10.0.0.12/32)

Route Allowed IPs: This needs to be checked; otherwise, the client won’t be able to access the subnet

Endpoint Host: Fill in during client setup. This section can be left blank

Endpoint Port: Fill in during client setup. This section can be left blank

Persistent Keep Alive: Fill in 25 (Maintain connection in NAT environment)

4. Firewall Settings

4.1 Open a listening port

Navigate to the menu bar NETWORK > Firewall, scroll to the bottom of the page, click the Add button below Zones, and then you will be redirected to the Zones Settings page.

Name: wgzone

Input: accept

Output: accept

Forward: accept

Masquerading: checked

MSS clamping: checked

Covered networks: wg0 (the WireGuard interface created in Step 3)

Allow forward to destination zones: lan

Allow forward from source zones: lan

Finally, click Save & Apply.

4.2 Traffic Rules

In the menu bar NETWORK > Firewall, click the tab labeled Traffic Rules, scroll to the bottom of the page, enter the policy name and protocol under Open ports on router, and then click the Add button. It will automatically navigate to the policy Settings page.

Name: Allow-WireGuard

Protocol: UDP

Destination port: 51820

Just keep the other Settings as default. Click “Save & Apply” to save the Settings.

4.3 Custom Rules

Set up NAT forwarding for bypass routing scenarios.

Click “Custom Rules” on the tab bar.

iptables -t nat -A POSTROUTING -s 10.0.0.0/24 -o br-lan -j MASQUERADE

After entering the command, click “Restart Firewall”.

5. Client settings

Here, we use WireGuard on macOS as an example.

5.1 Add Tunnel

Open WireGuard and add an Empty Tunnel, consistent with step 1.2 above.

5.2 Tunnel Settings

PrivateKey = QCqtyyhGWfci4xxxxxx(automatic generation)

Address: The IP address of the client is consistent with the Allowed IPs in step 3.2 above

DNS: The server-side LAN port IP address

PublicKey: Step 1.1 Public key information generated by the server

AllowedIPs: The IP network segment of the VPN channel and the network segment that communicates with the LAN port of the router

Endpoint: The server’s public IP address or domain name, along with port 51820

PersistentKeepalive: Maintain connection in a NAT environment

As shown in the figure, collect the public key information generated by the server and complete the client settings.

6. Verify wireguard

We can verify the connection status by pinging the server or client’s Tunnel IP to confirm if the tunnel has been successfully established. Typically, after the settings are configured correctly, the Tx/Rx data will be visible on the WireGuard interface, as shown in the figure.