Reference Manual for the Model RP614 v2 Web Safe Router
B-12 Networks, Routing, and Firewall Basics
Unlike simple Internet sharing routers, a firewall uses a process called stat eful packe t inspect ion to
ensure secure firewall filtering to protect your network from attacks and intrusions. Since
user-level applications such as FTP and Web browsers can create complex patterns of network
traffic, it is necessary for the firewall to analyze groups of network connection states. Using
stateful packet inspection, an incoming p acket is intercepted at the network layer and then
analyzed for state-related information associated with all network connections. A central cache
within the firewall keeps track of the state information associated with all network connections.
All traffic passing through the firewall is analyzed against the state of these connectio ns in order to
determine whether or not it will be allowed to pass through or be rejected.
Denial of Service AttackA hacker may be able to prevent your network from operating or communicating by launching a
Denial of Service (DoS) attack. The method used for such an attack can be as simple as merely
flooding your site with more requests than it can handle. A more sophisticated attack may attempt
to exploit some weakness in the operating system used by your router or gatewa y. Some operating
systems can be disrupted by simply sending a packet with incorrect length information.