Netgear WGR614v7 사용자 설명서

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54 Mbps Wireless Router WGR614v7 Reference Manual
B-10
Network, Routing, Firewall, and Basics
April 2006
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 wireless router has the capacity to act as a DHCP server.
The 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.
What is a Firewall?
A firewall is a device that protects one network from another, while allowing communication 
between the two. A firewall incorporates the functions of the NAT router, while adding features for 
dealing with a hacker intrusion or attack. Several known types of intrusion or attack can be 
recognized when they occur. When an incident is detected, the firewall can log details of the 
attempt, and can optionally send E-mail to an administrator notifying them of the incident. Using 
information from the log, the administrator can take action with the ISP of the hacker. In some 
types of intrusions, the firewall can fend off the hacker by discarding all further packets from the 
hacker’s IP address for a period of time.