Linksys BEFSR81 - EtherFast Cable/DSL Router User manual

A Division of Cisco Systems, Inc.
®
Model No.
WIRED with 8-Port Switch
Cable/DSL Router
BEFSR81
User Guide
EtherFast
®

EtherFast Cable/DSL Router with 8-Port Switch
Copyright and Trademarks
Linksys is a registered trademark or trademark of Cisco Systems, Inc. and/or its affiliates in the U.S. and certain
other countries. Copyright © 2003 Cisco Systems, Inc. All rights reserved.
How to Use this Guide
This User Guide has been designed to make understanding networking with the Router easier than ever. Look for
the following items when reading this Guide:
In addition to these symbols, there are definitions for technical terms that are presented like this:
Also, each figure (diagram, screenshot, or other image) is provided with a figure number and description, like
this:
Figure numbers and descriptions can also be found in the “List of Figures” section in the “Table of Contents”.
This exclamation point means there is a Caution or
Warning and is something that could damage your
property or the Router.
word: definition.
This checkmark means there is a Note of interest and
is something you should pay special attention to while
using the Router.
This question mark provides you with a reminder about
something you might need to do while using the Router.
Figure 0-1: Sample Figure Description
BEFSR81_V4-UG-30730NC JL

EtherFast Cable/DSL Router with 8-Port Switch
Table of Contents
Chapter 1: Introduction 1
Welcome 1
What’s in this Guide? 2
Chapter 2: Networking Basics 4
An Introduction to LANs 4
The Use of IP Addresses 4
Chapter 3: Getting to Know the Router 6
The Back Panel 6
The Front Panel 7
Chapter 4: Connecting the Router 8
Overview 8
Connection Instructions 9
Chapter 5: Configuring the PCs 10
Overview 10
Configuring Windows 98 and Millennium PCs 10
Configuring Windows 2000 PCs 11
Configuring Windows XP PCs 11
Chapter 6: Configuring the Router 13
Overview 13
Instructions 13
Chapter 7: Using The Router’s Web-based Utility 17
Overview 17
Navigating the Utility 17
Quick and Easy Administration 18
Basic Setup 19
DDNS 23
MAC Address Clone 24
Advanced Routing 25
Filter 26
VPN Passthrough 28
Port Range Forwarding 28
Port Triggering 29

EtherFast Cable/DSL Router with 8-Port Switch
UPnP Forwarding 30
DMZ 31
QoS 32
Management 33
Log 35
Factory Defaults 36
Firmware Upgrade 37
Router 37
Local Network 38
Appendix A: Troubleshooting 39
Common Problems and Solutions 39
Frequently Asked Questions 49
Appendix B: Upgrading Firmware 53
Appendix C: Finding the MAC Address and IP Address for Your
Ethernet Adapter 54
Windows 98 or Me Instructions 54
Windows 2000 or XP Instructions 54
For the Router’s Web-based Utility 55
Appendix D: Windows Help 56
Appendix E: Glossary 57
Appendix F: Specifications 63
Appendix G: Warranty Information 64
Appendix H: Regulatory Information 65
Appendix I: Contact Information 66

EtherFast Cable/DSL Router with 8-Port Switch
List of Figures
Figure 3-1: Back Panel 6
Figure 3-2: Front Panel 7
Figure 4-1: Example of a Typical Network 8
Figure 4-2: Connect a PC 9
Figure 4-3: Connect the Power 9
Figure 5-1: TCP/IP for Windows 98 and Me 10
Figure 5-2: Obtain an IP address automatically for Windows 98 and Me 10
Figure 5-3: Internet Protocol (TCP/IP) for Windows 2000 11
Figure 5-4: Obtain an IP address automatically for Windows 2000 11
Figure 5-5: Internet Protocol (TCP/IP) for Windows XP 12
Figure 5-6: Obtain an IP address automatically for Windows XP 12
Figure 6-1: Router’s IP Address for Basic Setup 13
Figure 6-2: Router Login for Basic Setup 13
Figure 6-3: Obtain an IP Automatically for Basic Setup 14
Figure 6-4: Static IP for Basic Setup 14
Figure 6-5: PPPoE for Basic Setup 15
Figure 6-6: RAS (for SingTel) for Basic Setup 15
Figure 6-7: PPTP for Basic Setup 16
Figure 6-8: Heart Beat Signal for Basic Setup 16
Figure 6-9: Router Registration for Basic Setup 16
Figure 7-1: Router’s IP Address 18
Figure 7-2: Router Login 18
Figure 7-3: Obtain an IP Automatically 19
Figure 7-4: Static IP 19
Figure 7-5: PPPoE 20
Figure 7-6: RAS (for Singtel) 20
Figure 7-7: PPTP 21
Figure 7-8: Heart Beat Signal 22

EtherFast Cable/DSL Router with 8-Port Switch
Figure 7-9: DDNS Disabled 23
Figure 7-10: DDNS Using DynDNS.org 24
Figure 7-11: DDNS Using TZO.com 24
Figure 7-12: MAC Clone 25
Figure 7-13: Advanced Routing 25
Figure 7-14: Routing Table 26
Figure 7-15: Filter 27
Figure 7-16: MAC Filter Setting 27
Figure 7-17: VPN Passthrough 28
Figure 7-18: Port Range Forwarding 28
Figure 7-19: Port Triggering 29
Figure 7-20: UPnP Forwarding 30
Figure 7-21: DMZ 32
Figure 7-22: QoS 32
Figure 7-23: Management 33
Figure 7-24: Log 35
Figure 7-25: Incoming Log Table 36
Figure 7-26: Outgoing Log Table 36
Figure 7-27: System Log 36
Figure 7-28: Factory Defaults 36
Figure 7-29: Firmware Upgrade 37
Figure 7-30: Router 37
Figure 7-31: Local Network 38
Figure 7-32: DHCP Active IP Table 38
Figure B-1: Upgrade Firmware 53
Figure C-1: IP Configuration Screen 54
Figure C-2: MAC Address/Adapter Address 54
Figure C-3: MAC Address/Physical Address 55
Figure C-4: MAC Address Filter 55
Figure C-5: MAC Address Clone 55

1
Chapter 1: Introduction
Welcome
EtherFast Cable/DSL Router with 8-Port Switch
Chapter 1: Introduction
Welcome
Thankyouforchoosing theEtherFast Cable/DSLRouter with8-Port Switch.This Routerwill allowyourcomputers
to share a high-speed Internet connection as well as resources, including files and printers.
How does the Router do all of this? By connecting your computers and peripherals to the Router and connecting
the Router to your cable or DSL modem, then the Router can direct and control communications for your network.
But what does all of this mean?
Networks are useful tools for sharing computer resources. You can access one printer from different computers
and access data located on another computer’s hard drive. Networks are even used for playing multiplayer video
games. So, networks not only are useful in homes and offices, but also can be fun.
PCs on a wired network create a LAN, or Local Area Network. They are connected with Ethernet cables, which is
why the network is called “wired”.
To create your network, install and set up the Router. To guide you through the process, Linksys strongly
recommends that you run the Setup Wizard on the Setup CD-ROM. If you prefer to manually set up the Router,
use the instructions in the Quick Installation or this User Guide to help you. These instructions should be all you
need to get the most out of the Router.
Ethernet: an IEEE standard network protocol
that specifies how data is placed on and
retrieved from a common transmission
medium.
LAN (Local Area Network): the computers
and networking products that make up the
network in your home or office.

2
Chapter 1: Introduction
What’s in this Guide?
EtherFast Cable/DSL Router with 8-Port Switch
What’s in this Guide?
This user guide covers the basic steps for setting up a network with a router. After going through “Chapter 3:
Getting to Know the Router,” most users will only need to use the following chapters:
• Chapter 4: Connecting the Router
This chapter instructs you on how to connect the cable or DSL modem to the Router and connect the PC(s) to
the Router.
• Chapter 5: Configuring the PCs
This chapter instructs you on how to configure your PC(s) for a DHCP connection, if the network settings are
not already set to DHCP.
• Chapter 6: Configuring 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.
You also have other chapter available for reference:
• Chapter 1: Introduction
This chapter describes the Router’s applications and this User Guide.
• Chapter 2: Networking Basics
This chapter briefly explains how a network functions.
• Chapter 7: Using the Router’s Web-based Utility
This chapter describes the Web-based Utility and the features available, so you can use and alter advanced
configuration settings.
• Appendix A: Troubleshooting
This appendix describes some possible problems and solutions, as well as frequently asked questions,
regarding installation and use of the Router.
• Appendix B: Upgrading Firmware
This appendix explains how you can upgrade the Router’s firmware.
• Appendix C: Finding the MAC Address and IP Address for Your Ethernet Adapter
This appendix instructs you on how to find the MAC address or Ethernet address of your PC’s Ethernet
network adapter.

3
Chapter 1: Introduction
What’s in this Guide?
EtherFast Cable/DSL Router with 8-Port Switch
• Appendix D: Windows Help
This appendix describes how you can use Windows Help for instructions about networking, such as installing
the TCP/IP protocol.
• Appendix E: Glossary
This appendix gives a brief glossary of terms frequently used in networking.
• Appendix F: Specifications
This appendix provides the technical specifications for the Router.
• Appendix G: Warranty Information
This appendix supplies the warranty information for the Router.
• Appendix H: Regulatory Information
This appendix supplies the regulatory information regarding the Router.
• Appendix J: Contact Information
This appendix provides contact information for a variety of Linksys resources, including Technical Support.

4
Chapter 2: Networking Basics
An Introduction to LANs
EtherFast Cable/DSL Router with 8-Port Switch
Chapter 2: Networking Basics
An Introduction to LANs
Simply put, a router is a network device that connects two networks together.
TheRouterconnects yourlocal area network(LAN), orthe group of PCs inyour homeor office, tothe Internet. The
Router processes and regulates the data that travels between these two networks.
The Router’s Network Address Translation (NAT) technology protects your network of PCs so users on the Internet
cannot “see” your PCs. This is how your LAN remains private. The Router protects your network by inspecting the
first packet coming in through the Internet port before delivery to the final destination on one of the Ethernet
ports. The Router inspects Internet port services like the web server, ftp server, or other Internet applications,
and, if allowed, it will forward the packet to the appropriate PC on the LAN side.
The Use of IP Addresses
IP stands for Internet Protocol. Every device in an IP-based network, including PCs, print servers, and routers,
requires an IP address to identify its location, or address, on the network. This applies to both the Internet and
LAN connections.
There are two ways of assigning IP addresses to your network devices.
A static IP address is a fixed IP address that you assign manually to a PC or other device on the network. Since a
static IP address remains valid until you disable it, static IP addressing ensures that the device assigned it will
always have that same IP address until you change it. Static IP addresses are commonly used with network
devices such as server PCs or print servers.
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 the information from your ISP.
A dynamic IP address is automatically assigned to a device on the network. These IP addresses are called
dynamic because they are only temporarily assigned to the PC or other 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.
Dynamic IP address: a temporary IP
address assigned by a DHCP server.
Static IP address: a fixed address
assigned to a computer or device that
is connected to a network.
NAT (Network Address Translation):
NAT technology translates IP
addresses of a local area network to a
different IP address for the Internet.
DHCP (Dynamic Host Configuration
Protocol): a protocol that lets one
device on a local network, known as a
DHCP server, assign temporary IP
addresses to the other network
devices, typically computers.