Netgear WGX102 참조 매뉴얼

B-10

Network, Routing, Firewall, and Basics

Many of the resources on the Internet can be addressed by simple descriptive names such as 

 

. This addressing is very helpful at the application level, but the 

descriptive name must be translated to an IP address in order for a user to actually contact the 
resource. Just as a telephone directory maps names to phone numbers, or as an ARP table maps IP 
addresses to MAC addresses, a domain name system (DNS) server maps descriptive names of 
network resources to IP addresses.

When a computer accesses a resource by its descriptive name, it first contacts a DNS server to 
obtain the IP address of the resource. The computer sends the desired message using the IP 
address. Many large organizations, such as ISPs, maintain their own DNS servers and allow their 
customers to use the servers to look up addresses.

When an IP-based local area network is installed, each computer must be configured with an 
IP address. If the computers need to access the Internet, they should also be configured with a 
gateway address and one or more DNS server addresses. As an alternative to manual 
configuration, there is a method by which each computer on the network can automatically obtain 
this configuration information. A device on the network may act as a Dynamic Host Configuration 
Protocol (DHCP) server. The DHCP server stores a list or pool of IP addresses, along with other 
information (such as gateway and DNS addresses) that it may assign to the other devices on the 
network. The WGX102 Wall-Plugged Range Extender has the capacity to act as a DHCP server.

The WGX102 Wall-Plugged Range Extender also functions as a DHCP client when connecting to 
the ISP. The firewall can automatically obtain an IP address, subnet mask, DNS server addresses, 
and a gateway address if the ISP provides this information by DHCP.

When your LAN connects to the Internet through a router, an opportunity is created for outsiders 
to access or disrupt your network. A NAT router provides some protection because by the very 
nature of the process, the network behind the router is shielded from access by outsiders on the 
Internet. However, there are methods by which a determined hacker can possibly obtain 
information about your network or at the least can disrupt your Internet access. A greater degree of 
protection is provided by a firewall router.