NAT NAT or Network Address Translation is the process that enables a single device such as a router or firewall to act as an agent between the Internet or Public Network and a local or private network. This “agent”, in real time, translates the source IP address of a device on one network interface, usually […]


IPv6 Internet Protocol version 6 (IPv6) will succeed IPv4 as the standard networking protocol of the Internet. IPv6 provides a number of advances over IPv4 but the primary reason for its replacing IPv4 is its limitation in addresses. IPv4 uses 32 bit addresses which means there is a theoretical limit of 2 to the power […]

Interfaces and Zones

Interfaces and Zones A Firewall is a gateway device that may be the nexus point for more than 2 networks. The interface that the traffic is coming in on and should be going out on is a fundamental concern for the purposes of routing as well as security. Routing, policies and addresses are all associated […]

FortiGate Modes

FortiGate Modes The FortiGate unit has a choice of modes that it can be used in, either NAT/Route mode or Transparent mode. The FortiGate unit is able to operate as a firewall in both modes, but some of its features are limited in Transparent mode. It is always best to choose which mode you are […]

Firewall concepts

Firewall concepts There are a number of foundational concepts that are necessary to have a grasp of before delving into the details of how the FortiGate firewall works. Some of these concepts are consistent throughout the firewall industry and some of them are specific to more advanced firewalls such as the FortiGate. Having a solid […]