A VPN (Virtual Private Network) allows you to establish a secure and encrypted connection between two or more systems using a public network, like the Internet.

The system supports two types of VPNs:

  1. roadwarrior: connect a remote client to the internal network
  2. net2net or tunnel: connect two remote networks


OpenVPN lets you easily create VPN connections, It brings with numerous advantages including:

  • Availability of clients for various operating systems: Windows, Linux, Apple, Android, iOS
  • Multiple NAT traversal, you do not need a dedicated static IP on the firewall
  • High stability
  • Simple configuration


The OpenVPN server in roadwarrior mode allows connection of multiple clients.

Supported authentication methods are:

  • System user and password
  • Certificate
  • System user, password and certificate

The server can operate in two modes: routed or bridged. You should choose bridged mode only if the tunnel must carry non-IP traffic.

To allow a client to establish a VPN:

  1. Create a new account: it is recommended to use a dedicated VPN account with certificate, avoiding the need to create a system user.

    On the other hand, it’s mandatory to choose a system account if you want to use authentication with user name and password.

  2. Download the file containing the configuration and certificates.

  3. Import the file into the client and start the VPN.

Tunnel (net2net)

When creating an OpenVPN net2net connection, you must choose a master between involved servers. All other servers are considered as slaves (clients).

Steps to be performed on the master server:

  • Enable roadwarrior server
  • Create a VPN-only account for each slave
  • During the account creation remember to specify the remote network configured behind the slave

Steps to be performed on the slave:

  • Create a client from the Client page, specifying the connection data to the master server.
  • Copy and paste the content of downloaded certificates from the master configuration page.


IPsec (IP Security) protocol is usually used to create tunnels with devices from other manufacturers.

Roadwarrior (L2TP)

L2TP is considered the replacement for PPTP which is insecure. Many devices include native support for this protocol but not all implementations are compatible.

Supported authentication methods are:

  • System user, password and certificate
  • Secret shared key (PSK)

To allow a client to establish a VPN:

  1. Configure the server as PDC (Primary Domain Controller) from the Windows Network page.
  2. Create a new system account.
  3. Download the file that contains certificates.
  4. Import client and CA (Certification Authority) certificates within the client.
  5. Proceed with the configuration of connection data and start the VPN.


Use of L2TP is recommended if and only if it is not possible to install a OpenVPN client into the device.

Tunnel (net2net)

IPsec is extremely reliable and compatible with many devices. In fact, it is an obvious choice when you need to create net2net connections between firewalls of different manufacturers.

Unlike OpenVPN configuration, in an IPsec tunnel, firewalls are considered peers.

If you are creating a tunnel between two NethServer, given the firewalls A and B:

  1. Configure the server A and specify the remote address and LAN of server B. If the Remote IP field is set to the special value %any, the server waits for connections from the other endpoint.
  2. Configure the second firewall B by mirroring the configuration from A inside the remote section. The special value %any is allowed in one side only!

If an endpoint is behind a NAT, the values for Local identifier and Remote identifier fields must be set to custom unique names prepended with @. Common names are the geographic locations of the servers, such as the state or city name.