Network Setup Overview; Chapter 2: Getting To Know The Etherfast Cable/Dsl Router With Qos And 8-Port Switch - Linksys BEFSR81 User Manual

If you use the Router to share your cable or DSL Internet connection, contact
your ISP to find out if they have assigned a static IP address to your account.
If so, you will need that static IP address when configuring the Router. You can
get that information from your ISP.
Note: Since the Router is a device that connects two networks, it
needs two IP addresses—one for the LAN, and one for the WAN. In
this User Guide, you'll see references to the "WAN IP address" and
the "LAN IP address."
Since the Router has firewall security (NAT), the only IP address that
can be seen from the Internet for your network is the Router's WAN IP
address.
However, even this WAN IP address can be blocked, so that the Router
and network seem invisible to the Internet—see the Blocking WAN
Requests description under IP Filtering in "Chapter 6: The Router's
Web-based Utility."
Dynamic IP Addresses
A dynamic IP address is automatically assigned to a device on the network,
such as PCs and print servers. These IP addresses are called "dynamic"
because they are only temporarily assigned to the PC or device. After a certain
time period, they expire and may change. If a PC logs onto the network (or the
Internet) and its dynamic IP address has expired, the DHCP server will assign
it a new dynamic IP address.
For DSL users, many ISPs may require you to log on with a user name and
password to gain access to the Internet. This is a dedicated, high-speed con-
nection type called Point to Point Protocol over Ethernet (PPPoE). PPPoE is
similar to a dial-up connection, but PPPoE does not dial a phone number when
establishing a connection. PPPoE also will provide the Router with a dynamic
IP address to establish a connection to the Internet.
DHCP (Dynamic Host Configuration Protocol) Servers
PCs and other network devices using dynamic IP addressing are assigned a new
IP address by a DHCP server. The PC or network device obtaining an IP
address is called the DHCP client. DHCP frees you from having to assign IP
addresses manually every time a new user is added to your network.
A DHCP server can either be a designated PC on the network or another net-
work device, such as the Router. By default, the Router's WAN setting is DHCP
client.
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Instant Broadband Series
®
EtherFast Cable/DSL Router with QoS and 8-Port Switch
®
By default, the Router can act as a DHCP server for your LAN. If you already
have a DHCP server running on your network, you must disable one of the two
DHCP servers. If you run more than one DHCP server on your network, you
will experience network errors, such as conflicting IP addresses. To disable
DHCP on the Router, see the DHCP section in "Chapter 6: The Router's Web-
based Utility."
Note: Even if you assign a static IP address to a PC, other PCs can
still use DHCP's dynamic IP addressing, as long as the static IP
address is not within the DHCP range of the LAN IP Addresses.
If the dynamic IP addressing fails to provide a dynamic IP address,
refer to "Appendix A: Troubleshooting."

Network Setup Overview

This user guide covers the basic steps for setting up a network with the Router.
After going through "Chapter 2: Getting to Know the EtherFast Cable/DSL
Router with QoS and 8-Port Switch," most users will only need to use the fol-
lowing chapters:
• Chapter 3: Connect the Router
This chapter instructs you on how to connect a cable or DSL modem to the
Router and connect your PC(s) to the Router.
• Chapter 4: Configure the PCs
This chapter instructs you on how to configure your PC(s) for a DHCP con-
nection, if the network settings are not already set to DHCP.
• Chapter 5: Configure the Router
This chapter explains how to configure the Router using your web browser
and the Router's web-based utility. You will configure the Router using the
settings provided by your ISP.
When you're finished with the basic steps, then you are ready to connect to the
Internet. After the PC(s) can access the Internet through the Router, you can
alter the Router's settings further; for example, you can adjust security features
and other settings to enable online gaming.
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