A firewall protects your network from the outside world. The D-Link DIR-655 offers a firewall type functionality. The SPI feature helps prevent cyber attacks. Sometimes you may want a computer exposed to the outside world for certain types of applications. If you choose to expose a computer, you cam enable DMZ. DMZ is short for Demilitarized Zone. This option will expose the chosen computer completely to the outside world.
SPI (Stateful Packet Inspection, also known as dynamic packet filtering) helps to prevent cyber attacks by tracking more state per session. It validates that the traffic passing through the session conforms to the protocol.
NAT Endpoint Filtering:
Select one of the following for TCP and UDP ports:
Endpoint Independent – Any incoming traffic sent to an open port will be forwarded to the application that opened the port. The port will close if idle for 5 minutes.
Address Restricted – Incoming traffic must match the IP address of the outgoing connection.
Address + Port Restriction – Incoming traffic must match the IP address and port of the outgoing connection.
Enable DMZ Host:
If an application has trouble working from behind the D-Link router, you can expose one computer to the Internet and run the application on that computer.
Note: Placing a computer in the DMZ may expose that computer to a variety of security risks. Use of this option is only recommended as a last resort.
Specify the IP address of the computer on the LAN that you want to have unrestricted Internet communication. If this computer obtains it’s IP address automatically using DHCP, be sure to make a static reservation on the Basic > DHCP page so that the IP address of the DMZ machine does not change.