NETGEAR CG814WG manual Ethernet Cabling, Stateful Packet Inspection

Hardware Manual for the Model CG814WG Wireless Cable Modem Gateway

Stateful Packet Inspection

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.

Ethernet Cabling

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 in Table D-1.

Table D-1.		UTP Ethernet cable wiring, straight-through
Pin	Wire color		Signal
1	Orange/White		Transmit (Tx) +
2	Orange		Transmit (Tx) -
3	Green/White		Receive (Rx) +
4	Blue
5	Blue/White
6	Green		Receive (Rx) -
7	Brown/White
8	Brown

Uplink Switches and Crossover Cables

In the wiring table, the concept of transmit and receive are from the perspective of the PC. For example, the PC transmits on pins 1 and 2. At the hub, the perspective is reversed, and the hub receives on pins 1 and 2. When connecting a PC to a PC, or a hub port to another hub port, the

Networks, Routing, and Firewall Basics D-11