Domain Name Server; Ip Configuration By Dhcp; Internet Security And Firewalls - NETGEAR FWG114P Reference Manual

Reference Manual for the ProSafe Wireless 802.11g Firewall/Print Server Model FWG114P

Domain Name Server

Many of the resources on the Internet can be addressed by simple descriptive names such as
www.NETGEAR.com. 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.

IP Configuration by DHCP

When an IP-based local area network is installed, each computer must be configured with an
IP address. If the PCs 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
FWG114P Wireless Firewall/Print Server has the capacity to act as a DHCP server.
The FWG114P Wireless Firewall/Print Server 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.
B-10 Network, Routing, and Firewall Basics
December 2003, M-10177-01