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Reference Manual for the 54 Mbps Wireless Router with Phone Adapter WGR826V
B-10 Network, Routing, and Firewall Basics
202-10051-01, March 2005
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.
IP Configuration by DHCP
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 WGR826V Wireless Router has the capacity to act as a DHCP server.
The WGR826V Wireless Router 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.
Internet Security and Firewalls
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.