Linksys BEFSR41 - EtherFast Cable/DSL Router User manual

A Division of Cisco Systems, Inc.
®
Model No.
WIRED
BEFSR41 (EU/UK/LA)
User Guide
with 4-Port Switch
Cable/DSL Router
EtherFast
®

EtherFast Cable/DSL Router with 4-Port Switch
Copyright and Trademarks
Specifications are subject to change without notice. Linksys and EtherFast are registered trademarks or
trademarks of Cisco Systems, Inc. and/or its affiliates in the U.S. and certain other countries. Copyright © 2004
Cisco Systems, Inc. All rights reserved. Other brands and product names are trademarks or registered
trademarks of their respective holders.
How to Use this Guide
Your guide to the EtherFast Cable/DSL Router with 4-Port Switch has been designed to make understanding
networking with the Router easier than ever. Look for the following items when reading this User 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.
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
BEFSR41_V4-UG-UK-41216NC KL

EtherFast Cable/DSL Router with 4-Port Switch
Chapter 1: Introduction 1
Welcome 1
What’s in this Guide? 2
Chapter 2: Networking Basics 4
An Introduction to Local Area Networks 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 Router 10
Overview 10
How to Access the Web-based Utility 11
The Setup Tab - Basic Setup 12
The Setup Tab - DDNS 18
The Setup Tab - MAC Address Clone 19
The Security Tab - Filter 22
The Security Tab - VPN 24
The Applications & Gaming Tab - Port Range Forwarding 25
The Applications & Gaming Tab - Port Triggering 26
The Applications & Gaming Tab - UPnP Forwarding 27
The Applications & Gaming Tab - DMZ 29
The Applications & Gaming Tab - QoS 30
The Administration Tab - Management 32
The Administration Tab - Log 34
The Administration Tab - Factory Defaults 35
The Administration Tab - Firmware Upgrade 36
The Status Tab - Router 37
The Status Tab - Local Network 38
Appendix A: Troubleshooting 39
Common Problems and Solutions 39
Frequently Asked Questions 49
Appendix B: Upgrading Firmware 53

EtherFast Cable/DSL Router with 4-Port Switch
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 62
Appendix G: Warranty Information 63
Appendix H: Regulatory Information and Safety 64
Appendix I: Contact Information 71

EtherFast Cable/DSL Router with 4-Port Switch
Figure 3-1: Back Panel 6
Figure 3-2: Front Panel 7
Figure 4-1: Example of a Typical Network 9
Figure 4-2: Connect a PC 9
Figure 4-3: Connect the Cable/DSL Modem 9
Figure 4-4: Connect the Power 9
Figure 5-1: Router’s IP Address 11
Figure 5-2: Router Login 11
Figure 5-3: Setup Tab - Basic Setup
(Obtain an IP automatically) 12
Figure 5-4: Static IP 13
Figure 5-5: PPPoE 13
Figure 5-6: RAS 14
Figure 5-7: PPTP 14
Figure 5-8: Heart Beat Signal 15
Figure 5-9: L2TP 16
Figure 5-10: Setup Tab - DDNS (DynDNS.org) 18
Figure 5-11: Setup Tab - DDNS (TZO.com) 18
Figure 5-12: Setup Tab - MAC Address Clone 19
Figure 5-13: Setup Tab - Advanced Routing 20
Figure 5-14: Routing Table Entry List 21
Figure 5-15: Security Tab - Firewall 22
Figure 5-16: MAC Filter Setting 22
Figure 5-17: Security Tab - VPN Passthrough 24
Figure 5-18: Applications & Gaming Tab -
Port Range Forwarding 25
Figure 5-19: Applications & Gaming Tab -
Port Triggering 26
Figure 5-20: Applications & Gaming Tab -
UPnP Forwarding 27

EtherFast Cable/DSL Router with 4-Port Switch
Figure 5-21: Applications & Gaming Tab - DMZ 29
Figure 5-22: Applications & Gaming Tab - QoS 30
Figure 5-23: Administration Tab - Management 32
Figure 5-24: Administration Tab - Log 34
Figure 5-25: Incoming Log Table 34
Figure 5-26: Outgoing Log Table 34
Figure 5-27: System Log 34
Figure 5-28: Administration Tab - Factory Defaults 35
Figure 5-29: Administration Tab - Firmware Upgrade 36
Figure 5-30: Status Tab - Router 37
Figure 5-31: Status Tab - Local Network 38
Figure 5-32: DHCP Client 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 Filtering 55
Figure C-5: MAC Address Clone 55

1
Chapter 1: Introduction
Welcome
EtherFast Cable/DSL Router with 4-Port Switch
Chapter 1: Introduction
Welcome
Thank you for choosing the EtherFast Cable/DSL Router with 4-Port Switch. This Router will allow your computers
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 Internet access and computer resources. Multiple computers can share
Internet access, so you don’t need more than one high-speed Internet connection. 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 4-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 Router to your cable or DSL modem, PCs, and peripherals,
such as a printer.
• Chapter 5: 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.
• 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.
• 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.

3
Chapter 1: Introduction
What’s in this Guide?
EtherFast Cable/DSL Router with 4-Port Switch
• 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 I: Contact Information
This appendix provides contact information for a variety of Linksys resources, including Technical Support.

4
Chapter 2: Networking Basics
An Introduction to Local Area Networks
EtherFast Cable/DSL Router with 4-Port Switch
Chapter 2: Networking Basics
An Introduction to Local Area Networks
Simply put, a router is a network device that connects two networks together.
The Router connects your local area network (LAN), or the group of PCs in your home or office, to the 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