Firewall/VPN

What is a firewall?

A firewall is a device used in a computer network to control communications, allowing or blocking them according to the policies defined by the organization responsible for the network.

GRN can take care of the installation and configuration of firewalls, either by conventional solutions based on Zeroshell configurations or custom designed for special requirements. In addition to filtering traffic from the Internet, a firewall can do much more:

  • Proxy service (transparent or not) for faster browsing.
  • Whitelists and blacklists service to control user access to certain domains (eg facebook, twitter, etc…)
  • Load balancing service between different connections to the Internet.
  • Servei de backup entre diferents connexions a Internet per tal que si la vostra connexió principal deixa de funcionar passareu automàticament a la de reserva.
  • Backup service between different Internet connections so that if your primary connection fails, the system automatically switches to the other one.
  • VPN service with PPTP, IPSec or OpenVPN.
  • Routing policy service to select the services that are used in different Internet connections.

Depending on the requirements needed, we have two different hardware platforms


For medium or small sized installations, we have a solution with 3 Ethernet ports. It is an embedded device called ALIX with 3 Ethernet connections and flash memory. Ideal as a firewall and VPN server in small-scale networks.


For large installations or when a proxy server functionality is required we use a device based on Intel Atom processor that has 2 Ethernet connections. The number of Ethernet ports can be expanded, so that we can have configurations with 2, 3, 4 and 6 Ethernets, all of them Gigabit and Intel chipset-based.

The device can work with disks or flash memories. If proxy service is needed, we recommend using disks, which can also be installed on RAID1.


In the case of a headquarter connectivity with various secondary offices, a good idea is to give the central Intel Atom based device and use the Alix device for delegations connectivity.

GRN’s value added

  • We have ways of diagnosing complex problems on your network that cause poor performance such as viruses, download programs, etc. ..
  • With our connectivity solutions that we can manage the installation in both ends by different technologies (wimax, adsl,…).