Netgear WGX102 사용자 설명서

Network, Routing, Firewall, and Basics

B-11

Unlike simple Internet sharing routers, a firewall uses a process called stateful packet inspection 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 packet 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 connections in order to 
determine whether or not it will be allowed to pass through or rejected.

A 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 gateway. Some operating 
systems can be disrupted by simply sending a packet with incorrect length information.

Although Ethernet networks originally used thick or thin coaxial cable, most installations currently 
use unshielded twisted pair (UTP) cabling. The UTP cable contains eight conductors, arranged in 
four twisted pairs, and terminated with an RJ45 type connector. A normal straight-through UTP 
Ethernet cable follows the EIA568B standard wiring as described below in