Netgear WGT624 User Manual download pdf (Page 100)

Reference Manual for the 108 Mbps Wireless Firewall Router WGT624

B-8 Network, Routing, Firewall, and Basics

M-10153-01

The following figure illustrates a single IP address operation.

Figure 7-3: Single IP Address Operation Using NAT

This scheme offers the additional benefit of firewall-like protection because the internal LAN

addresses are not available to the Internet through the translated connection. All incoming

inquiries are filtered out by the router. This filtering can prevent intruders from probing your

system. However, using port forwarding, you can allow one PC (for example, a web server) on

your local network to be accessible to outside users.

MAC Addresses and Address Resolution Protocol

An IP address alone cannot be used to deliver data from one LAN device to another. To send data

between LAN devices, you must convert the IP address of the destination device to its media

access control (MAC) address. Each device on an Ethernet network has a unique MAC address,

which is a 48-bit number assigned to each device by the manufacturer. The technique that

associates the IP address with a MAC address is known as address resolution. Internet Protocol

uses the Address Resolution Protocol (ARP) to resolve MAC addresses.

92.168.0.2

92.168.0.3

92.168.0.4

92.168.0.5

192.168.0.1 172.21.15.105

Private IP addresses

assigned by user

Internet

IP addresses

assigned by ISP

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Netgear WGT624 User Manual Page 100