OpenVPN Access Control

Introduction

In this example, we will configure an OpenVPN server and will manage which resources can be accessed by separate clients

Generating certificates for an OpenVPN server

1)Navigate to System -> Administration -> Certificates

2)Generate 2 certificates with a keysize 1024:

2.1) CA

2.2) Server

3) In Certificate Manager download Server certificate

For any OpenVPN clients, You will need to generate “Client” certificates, download certificate and key, and send them to the client

Creating an OpenVPN server

1) Connect to WebUI and enable Advanced mode

2) Navigate to Services -> VPN -> OpenVPN

3) Add a new OpenVPN instance with a Server role

4) Create an OpenVPN server with these settings

Virtual network IP address – 10.0.0.0

Virtual network netmask – 255.255.255.240

Client to client – disabled

Certificate files from device - on

5) Press "Save & Apply", enable OpenVPN server and check if the server is online

Connecting clients to the OpenVPN server

1) Navigate to Services -> VPN -> OpenVPN

2) Add a new OpenVPN instance with a Client role

3) Create an OpenVPN client with these settings

Remote host/IP address - Public IP of the OpenVPN server's router . Remote network IP address - 10.0.0.0

Remote network netmask - 255.255.255.240

And add the certificates from the OpenVPN server - Certificate Authority, Client certificate and Client key which we downloaded in Certificate Generation step

4) Press "Save & Apply", enable OpenVPN client and check if the connection is made

5) Repeat this step for as many clients as You need. For this example, we will have 3 clients

Client to Client LAN network communication

This step should be done on OpenVPN server and all clients that want their LAN subnets be accessible and to access other client's LAN subnets

1) Navigate to Network -> Firewall -> General settings -> Zones and set OpenVPN zone to forward traffic to LAN

This step should be done on all clients that want their LAN subnets be accessible and to access other client's LAN subnets

1) Create a route to other client LAN networks using WebUI or CLI. To create route from client 1's LAN to client 2's LAN using CLI use this command

ip route add 192.168.20.0/24 via 10.0.0.6

Controlling access with firewall

1) Navigate to Network -> Firewall -> Access Control

2) Create a new deny rule. In this example, we are denying Client 3 from accessing any other clients and their LAN networks

Source interface - OpenVPN

Destination interface - OpenVPN

Source IP - OpenVPN remote IP and LAN subnet of client 3

Destination IP - other client OpenVPN remote endpoints and LAN subnets

This rule will deny all traffic from Client 3 to other clients, but will not interact with traffic, if it's destination is OpenVPN server or it's LAN subnet