3Com 3CRWDR300A-73-US User Guide - Page 92

90 CHAPTER 5: CONFIGURING THE ROUTER Firewall This section is for configuration settings of the Router's firewall function. Your Router is equipped with a firewall that will protect your network from a wide array of common hacker attacks including Ping of Death (PoD) and Denial of Service (DoS) attacks. You can turn the firewall function off if needed. Turning off the firewall protection will not leave your network completely vulnerable to hacker attacks, but 3Com recommends that you leave the firewall enabled whenever possible. SPI Stateful Packet Inspection (SPI) - The Intrusion Detection Feature of the Router limits access for incoming traffic at the WAN port. This feature is called a "stateful" packet inspection, because it examines the contents of the packet to determine the state of the communications; i.e., it ensures that the stated destination computer has previously requested the current communication. This is a way of ensuring that all communications are initiated by the recipient computer and are taking place only with sources that are known and trusted from previous interactions. In addition to being more rigorous in their inspection of packets, stateful inspection firewalls also close off ports until connection to the specific port is requested. Figure 68 Firewall Screen