3Com WL-550 User Manual

Wireless 11g Cable/DSL Router

User Guide

WL-550

3CRWER101U-75
3CRWER101E-75
3CRWER101A-75

http://www.3Com.com/

Part No. 10016641 Rev. AA

Published March 2008

3Com Corporation
350 Campus Drive,
Marlborough, MA
USA 01752-3064

Copyright © 2008, 3Com Corporation. All rights reserved. No part of this documentation may be reproduced
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3Com, and the 3Com logo are registered trademarks of 3Com Corporation.
Intel and Pentium are registered trademarks of Intel Corporation. Microsoft, MS-DOS, Windows, and Windows

NT are registered trademarks of Microsoft Corporation. Novell and NetWare are registered trademarks of
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ABOUT THIS GUIDE

Naming Convention 5
Conventions 6
Feedback About This User Guide 7
Related Documentation 7

INTRODUCING THE ROUTER

Wireless 11g Cable/DSL Router 9
Router Advantages 11
Package Contents 11
Minimum System and Component Requirements 12
Physical Features 12

INSTALLING THE ROUTER

Introduction 17
Positioning the Router 17
Powering Up the Router 18
Connecting the Router to the Internet 18
Connecting the Router to LAN 18
Setting up your computers for networking with the Router 20

1

2

SETTING UP YOUR COMPUTERS

Obtaining an IP Address Automatically 23

Windows 2000 23
Windows XP 23
Windows Vista 25

3

Macintosh 27
Disabling PPPoE and PPTP Client Software 28
Disabling Web Proxy 28

RUNNING THE SETUP WIZARD

Accessing the Setup Wizard 29

Setup Wizard - Wireless Settings 31

Setup Wizard - Connection Settings 32

CONFIGURING THE ROUTER

Navigating Through the Router Configuration screens 39

Main Menu 39
Network Settings 39

Status 39

LAN Settings 41

WAN Settings 43

Wireless 48
Firewall 57

Schedule Rule 58

Access Control 60

MAC Filter 62

URL Filtering 63

Intrusion Detection 64

DMZ 69
Maintenance 70

Configuration Tools 70

Firmware Upgrade 71

Restart Router 72
Advanced Settings 72

NAT 73

4

5

System 78
UPNP 82
DNS 83
DDNS 84
Routing 85
Static Routes 85
RIP 86
Routing Table 87

TROUBLESHOOTING

Basic Connection Checks 89
Browsing to the Router Configuration Screens 89
Connecting to the Internet 90
Forgotten Password and Reset to Factory Defaults 90
Wireless Networking 91
Recovering from Corrupted Software 93
Frequently Asked Questions 94

6

IP ADDRESSING

The Internet Protocol Suite 95
Managing the Router over the Network 95

IP Addresses and Subnet Masks 95

How does a Device Obtain an IP Address and Subnet Mask? 97

DHCP Addressing 97
Static Addressing 97
Auto-IP Addressing 97

A

TECHNICAL SPECIFICATIONS

Wireless 11g Cable/DSL Router 99

Standards 100

System Requirements 100

END USER SOFTWARE LICENSE AGREEMENT

OBTAINING SUPPORT FOR YOUR PRODUCT

GLOSSARY

B

C

D

REGULATORY NOTICES

INDEX

ABOUT THIS GUIDE

This guide describes how to install and configure the 3Com Wireless 11g
Cable/DSL Router (3CRWER101x-75).

This guide is intended for use by those responsible for installing and
setting up network equipment; consequently, it assumes a basic working
knowledge of LANs (Local Area Networks) and Internet Routers.

If a release note is shipped with the 3Com Wireless 11g Cable/DSL Router
and contains information that differs from the information in this guide,
follow the information in the release note.

Most user guides and release notes are available in Adobe Acrobat
Reader Portable Document Format (PDF) on the 3Com World Wide Web
site:

http://www.3Com.com

Naming Convention Throughout this guide, the 3Com Wireless 11g Cable/DSL Router is

referred to as the “Router”.

Category 3 and Category 5 Twisted Pair Cables are referred to as Twisted
Pair Cables throughout this guide.

6 ABOUT THIS GUIDE

Conventions Ta bl e 1 and Tab l e 2 list conventions that are used throughout this guide.

Tab le 1 Notice Icons

Icon Notice Type Description

Information note Information that describes important features or

instructions.

Caution Information that alerts you to potential loss of data or

potential damage to an application, system, or device.

Warning Information that alerts you to potential personal

injury.

Tab le 2 Text Conventions

Convention Description

The words “enter”
and “type”

Keyboard key names If you must press two or more keys simultaneously, the key

Words in italics Italics are used to:

When you see the word “enter” in this guide, you must type
something, and then press Return or Enter. Do not press
Return or Enter when an instruction simply says “type.”

names are linked with a plus sign (+). Example:

Press Ctrl+Alt+Del

■ Emphasize a point.

■ Denote a new term at the place where it is defined in the

text.

■ Identify menu names, menu commands, and software

button names. Examples:

From the Help menu, select Contents.

Click OK.

Feedback About This User Guide 7

Feedback About This User Guide

Related Documentation

Your suggestions are very important to us. They will help make our
documentation more useful to you. Please e-mail comments about this
document to 3Com at:

[e-mail]

Please include the following information when commenting:

■ Document title

■ Document part number (on the title page)

■ Page number (if appropriate)

Example:

■ 3Com Wireless 11g Cable/DSL Router User Guide

■ Part Number 149100059700J Rev. AA

■ Page 24

Do not use this e-mail address for technical support questions. For
information about contacting Technical Support, please refer to

Appendix C

.

In addition to this guide, each Router document set includes one
Installation Guide. This guide contains the instructions you need to install
and configure your Router.

8 ABOUT THIS GUIDE

1

INTRODUCING THE ROUTER

Welcome to the world of networking with 3Com®. In the modern
business environment, communication and sharing information is crucial.
Computer networks have proved to be one of the fastest modes of
communication but, until recently, only large businesses could afford the
networking advantage.

Wireless 11g Cable/DSL Router

The Wireless 11g Cable/DSL Router is designed to provide a cost-effective
means of sharing a single broadband Internet connection amongst
several wired and wireless computers. The Router also provides protection
in the form of an electronic “firewall” preventing anyone outside of your
network from seeing your files or damaging your computers. The Router
can also prevent your users from accessing Web sites which you find
unsuitable.

Figure 1

only one computer is connected to the Internet. This computer must
always be powered on for the other computers on the network to access
the Internet.

shows an example network without a Router. In this network,

10 CHAPTER 1: INTRODUCING THE ROUTER

Figure 1 Example Network Without a Router

When you use the Router in your network (Figure 2), it becomes your
connection to the Internet. Connections can be made directly to the
Router, or to an OfficeConnect Switch, expanding the number of
computers you can have in your network.

Figure 2 Example Network Using a Firewall Router

Router Advantages The advantages of the Router include:

■ Shared Internet connection for both wired and wireless computers

■ High speed 802.11g wireless networking

■ No need for a dedicated, “always on” computer serving as your

Internet connection

■ Cross-platform operation for compatibility with Windows, Unix and

Macintosh computers

■ Easy-to-use, Web-based setup and configuration

■ Provides centralization of all network address settings (DHCP)

■ Acts as a Virtual server to enable remote access to Web, FTP, and other

services on your network

■ Security — Firewall protection against Internet hacker attacks and

encryption to protect wireless network traffic

Package Contents The Router kit includes the following items:

Router Advantages 11

■ One Wireless 11g Cable/DSL Router

■ One power adapter for use with the Router

■ One Ethernet cable

■ One Detachable antenna

■ One CD-ROM containing this User Guide

■ Installation Guide

■ Support and Safety Information Sheet

■ Warranty Flyer

If any of these items are missing or damaged, please contact your retailer.

12 CHAPTER 1: INTRODUCING THE ROUTER

Minimum System and Component Requirements

Your Router requires that the computer(s) and components in your
network be configured with at least the following:

■ A computer with an operating system that supports TCP/IP

networking protocols (for example Windows 98/NT/Me/2000/
XP/Vista, Unix, Mac OS 8.5 or higher).

■ An Ethernet 10 Mbps or 10/100 Mbps NIC for each computer to be

connected to the four-port switch on your Router.

OR

An 802.11b or 802.11g wireless NIC.

■ Internet access from your local telephone company or Internet Service

Provider (ISP) using a DSL modem or cable modem.

■ A Web browser that supports JavaScript, such as Netscape 4.7 or

higher, Internet Explorer 5.0 or higher, or Mozilla 1.2.1 or higher.

Physical Features The top panel of the Router contains a series of indicator lights (LEDs)

that help describe the state of various networking and connection
operations.

Figure 3 Router - Top View

Physical Features 13

1Power LED

Green

Indicates that the Router is powered on, and the boot up is successful.

2 WLAN Status LED

Green

If the LED is on it indicates that wireless networking is enabled. If the LED
is flashing, the link is OK and data is being transmitted or received. If the
LED is off, the Wireless LAN has been disabled in the Router, or there is a
problem. Refer to Chapter 6

“Troubleshooting”.

3 WAN Status LED

Green

If the LED is on it indicates that the WAN port has established a valid
Ethernet network connection. If the LED is flashing, the link is OK and
data is being transmitted or received. If the LED is off, the WAN has been
disabled in the Router, or there is a problem. Refer to Chapter 6

Troubleshooting”.

“

4 LAN Status LEDs

Green

If the LED is on, the link between the port and the next piece of network
equipment is OK. If the LED is flashing, the link is OK and data is being
transmitted or received. If the LED is off, nothing is connected, or the
connected device is switched off, or there is a problem with the
connection (refer to Chapter 6

“Troubleshooting”). The port will

automatically adjust to the correct speed and duplex.

The rear panel (Figure 4

) of the Router contains one WAN port, four LAN

ports, and a power adapter socket.

Figure 4 Router - Rear Panel

14 CHAPTER 1: INTRODUCING THE ROUTER

5WAN Port

Using the RJ-45 cable provided, you should connect your cable modem,
DSL modem, or an Ethernet router to this port.

6 LAN Ports

Using suitable RJ-45 cables, you can connect your Router to a computer,
or to any other piece of equipment that has an Ethernet connection (for
example, a hub or a switch). These ports have an automatic MDI/MDIX
feature, which means either straight-through or a crossover cable can be
used.

7 Power Adapter Socket

Only use the power adapter that is supplied with this Router. Do not use
any other adapter.

8 Wireless Antenna

Be sure the detachable external antenna is connected to the Router
before setting up your wireless LAN. Try to place the Wireless 11g Router
in a position that is located in the center of your wireless network. The
higher you place the antenna, the better the performance.

A reset bottom is locadted on the bottom of the Router (Figure 5

Figure 5 Router - Bottom Panel

Reset Button

).

Physical Features 15

9 Reset Button

The reset button allows you to reboot the Router, or to restore the default
factory settings. Push for one second to perform a system reboot. All of
your settings will remain upon restarting. Push for 8 seconds to reset the
Router to the factory default settings.

To perform a system reset without losing configuration settings, click the
Restart Router button on the web management screen. The
configurations that you have set previously will not be changed back to
the factory default settings. Refer to “Restart Router”

.

16 CHAPTER 1: INTRODUCING THE ROUTER

INSTALLING THE ROUTER

2

Introduction This chapter will guide you through a basic installation of the Router,

including:

■ Connecting the Router to the Internet.

■ Connecting the Router to your network.

■ Setting up your computers for networking with the Router.

CAUTION: Be sure to attach the removable antenna to the Router before
connecting to your wireless network.

Positioning the Router

You should place the Router in a location that:

■ is conveniently located for connection to the cable or ADSL modem.

■ is centrally located to the wireless computers that will connect to the

Router. A suitable location might be on top of a high shelf or similar
furniture to optimize wireless connections to computers in both
horizontal and vertical directions, allowing wider coverage.

■ allows convenient connection to the computers that will be connected

to the four LAN ports on the rear panel, if desired.

■ allows easy viewing of the top panel LED indicator lights, and access

to the rear panel connectors, if necessary.

When positioning your Router, ensure:

■ It is out of direct sunlight and away from sources of heat.

■ Cabling is away from power lines, fluorescent lighting fixtures, and

sources of electrical noise such as radios, transmitters and broadband
amplifiers.

■ Water or moisture cannot enter the case of the unit.

18 CHAPTER 2: INSTALLING THE ROUTER

■ Air flow around the unit and through the vents in the side of the case

is not restricted. 3Com recommends you provide a minimum of
25 mm (1 in.) clearance.

Powering Up the Router

Connecting the Router to the Internet

To power up the Router:

1 Plug the power adapter into the power adapter socket located on the

back panel of the Router.

2 Plug the power adapter into a standard electrical wall socket.

Prepare an Ethernet cable for connecting the WAN port of the Wireless
11g Router to the RJ-45 port of the broadband xDSL or cable modem.
See Figure 6

Figure 6 Connecting the Router to the Internet

:

Connecting the Router to LAN

The four LAN ports on the Router auto-negotiate the connection speed to
10 Mbps Ethernet or 100 Mbps Fast Ethernet, as well as the transmission
mode to half duplex or full duplex.

Connecting the Router to LAN 19

Use RJ-45 cables to connect any of the four LAN ports on the Router to
an Ethernet adapter on your PC. Otherwise, cascade any of the LAN ports
on the Router to an Ethernet hub or switch, and then connect your PC or
other network equipment to the hub or switch. When inserting an RJ-45
connector, be sure the tab on the connector clicks into position to ensure
that it is properly seated. See Figure 7

Figure 7 Connecting the LAN

:

You have now completed the hardware installation of your Router. Next
you need to set up your computers so that they can make use of the
Router to communicate with the Internet.

3Com recommends that you perform the initial Router configuration
from a computer that is directly connected to one of the LAN ports.

If you configure the Router from a wireless computer, note that you may
lose contact with the Router if you change the wireless configuration.

To communicate wirelessly with your Router, your wireless NIC should be
set as follows:

■ Encryption — none

■ SSID — 3Com

■ Channel — 6

20 CHAPTER 2: INSTALLING THE ROUTER

Setting up your computers for networking with the Router

You may also connect the Router to your PC (using a wireless client
adapter) via radio signals. Install a wireless network adapter in each
computer that will be connected to the Internet or your local network via
radio signals.

Place the Router in a position that gives it maximum coverage. Try to
place the Router in a position that is located in the center of your wireless
network. Normally, the higher you place the antenna, the better the
performance. Ensure that the Router’s location provides optimal reception
throughout your home or office.

Computers equipped with a wireless adapter can communicate with each
other as an independent wireless LAN by configuring each computer to
the same radio channel. However, the Router can provide access to your
wired/wireless LAN or to the Internet for all wireless workstations. Each
wireless PC in this network infrastructure can talk to any computer in the
wireless group via a radio link, or access other computers or network
resources in the wired LAN infrastructure or over the Internet via the
Router.

The wireless infrastructure configuration not only extends the accessibility
of wireless PCs to the wired LAN, but also increases the effective wireless
transmission range for wireless PCs by retransmitting incoming radio
signals through the Router.

A wireless infrastructure can be used for access to a central database, or
for connection between mobile workers, See Figure 8

:

Setting up your computers for networking with the Router 21

Figure 8 WLAN Connections

22 CHAPTER 2: INSTALLING THE ROUTER

3

Obtaining an IP Address Automatically

Windows 2000 If you are using a Windows 2000-based computer, use the following

SETTING UP YOUR COMPUTERS

The Router has the ability to dynamically allocate network addresses to
the computers on your network, using DHCP. However, your computers
need to be configured correctly for this to take place. To change the
configuration of your computers to allow this, follow the instructions in
this chapter.

procedure to change your TCP/IP settings:

1 From the Windows Start Menu, select Settings > Control Panel.

Windows XP

2 Double click on Network and Dial-Up Connections.

3 Double click on Local Area Connection.

4 Click on Properties.

5 Select Internet Protocol TCP/IP and click on Properties.

6 Ensure that the options Obtain an IP address automatically, and Obtain

DNS server address automatically are both selected. Click OK.

7 Restart your computer.

1 From the Windows Start Menu, select Control Panel.

2 Click on Network and Internet Connections.

3 Click on the Network Connections icon.

24 CHAPTER 3: SETTING UP YOUR COMPUTERS

4 Double click on LAN or High Speed Connection icon. A screen titled Local

Area Connection Status will appear.

5 A screen similar to Figure 9

should be displayed. Select Internet Protocol

TCP/IP and click on Properties.

Figure 9 Local Area Connection Properties Screen

6 Ensure that the options Obtain an IP address automatically, and Obtain

DNS servers automatically are both selected as shown in Figure 10

.

Click OK.

Obtaining an IP Address Automatically 25

Figure 10 Internet Protocol (TCP/IP) Properties Screen

7 Restart your computer.

Windows Vista

1 From the Windows Start Menu, select Settings > Network.

2 Click on Organize. Select Properties.

3 Click on Manage network>Connections.

4 Double click Local Area Connection. Select Properties and click continue.

5 A screen similar to Figure 11

should be displayed. Select Internet Protocol

Version 6,Version 4 (TCP/IPv6,v4) and click on Properties.

26 CHAPTER 3: SETTING UP YOUR COMPUTERS

Figure 11 Local Area Connection Properties Screen

6 Ensure that the options Obtain an IPv6,v4 address automatically, and

Obtain DNS servers address automatically are both selected as shown in

Figure 12

. Click OK.

Figure 12 Internet Protocol Version 6 (TCP/IPv6) Properties Screen

Obtaining an IP Address Automatically 27

Macintosh If you are using a Macintosh computer, use the following procedure to

change your TCP/IP settings:

1 From the desktop, select Apple Menu, Control Panels, and TCP/IP.

2 In the TCP/IP control panel, set Connect Via: to Ethernet.

3 In the TCP/IP control panel, set Configure: to Using DHCP Server.

4 Close the TCP/IP dialog box, and save your changes.

5 Restart your computer.

28 CHAPTER 3: SETTING UP YOUR COMPUTERS

Disabling PPPoE and PPTP Client Software

If you have PPPoE client software installed on your computer, you will
need to disable it. To do this:

1 From the Windows Start Menu, select Control Panel > Network and

Internet Connections.

2 Double click on Internet Options.

3 Select the Connections Tab. A screen similar to Figure 13

displayed.

4 Select the Never dial a connection option.

Figure 13 Internet Properties Screen

should be

Disabling Web Proxy

You may want to remove the PPPoE client software from your computer
to free resources, as it is not required for use with the Router.

Ensure that you do not have a web proxy enabled on your computer.

Go to the Control Panel and click on Internet Options. Select the
Connections tab and click LAN Settings at the bottom. Make sure that
the Use Proxy Server option is unchecked.

4

RUNNING THE SETUP WIZARD

Accessing the Setup Wizard

The Router setup program is Web-based, which means that it is accessed
through your Web browser (Netscape Navigator 4.7 or higher, Internet
Explorer 5.5 or higher, or Mozilla 1.2.1 or higher).

To use the Setup Wizard:

1 Ensure that you have at least one computer connected to the Router.

Refer to Chapter 2

2 Launch your Web browser on the computer.

3 Enter the following URL in the location or address field of your browser:

http://192.168.1.1 (Figure 14

Figure 14 Web Browser Location Field (Factory Default)

for details on how to do this.

). The Login screen displays.

30 CHAPTER 4: RUNNING THE SETUP WIZARD

4 To log in as an administrator, enter the password (the default password is

admin) in the System Password field and click Log in (Figure 15

Figure 15 Router Login Screen

).

5 When you have logged in,

■ if you are logging in for the first time, the Country Selection screen

will appear (Figure 16

). Please select the country form the drop-down

menu, and click Apply.

Figure 16 Country Selection Screen

The Status page will then launch automatically (refer to Figure 17).

Accessing the Setup Wizard 31

Figure 17 Status Screen

Then click on Setup Wizard and you will be guided step by step through a
basic setup procedure.

Setup Wizard -

Wireless Settings

The first item in the Setup Wizard is Getting Started. Click NEXT to
proceed to the following screen and configure your Wireless Settings.

The Wireless Settings screen allows you to set up your wireless network
settings. You must specify a common radio channel and SSID (Service Set
ID) to be used by the Router and all of its wireless clients. Be sure you
configure all of its clients to the same value. For security purposes, you
should change the default SSID immediately.

32 CHAPTER 4: RUNNING THE SETUP WIZARD

Figure 18 Wireless Settings Screen

■ Wireless Network Name (SSID): The Service Set ID (SSID) is the name

of your wireless network. The SSID must be the same on the Router
and all of its wireless clients. (Default: 3Com)

Setup Wizard -

Connection Settings

■ Broadcast Wireless Network Name: Enable or disable the broadcasting

of the SSID. If you disable broadcast of the SSID, only devices that
have the correct SSID can connect. (Default: Enable)

■ Wireless Mode: This device supports the following modes -11g only,

11b only, and 11b/g mixed mode. (Default: 11b/g mixed mode)

■ Wi-Fi Channel Number: The radio channel used by the Router and its

clients to communicate with each other. This channel must be the
same on the Router and all of its wireless clients. The Router will
automatically assign itself a radio channel, or you may select one
manually. (Default: 6)

■ Extend Range: Increases the range of the Router. (Default: Disable)

The Connection Settings screen allows you to set up the Router for the
type of Internet connection you have. Before setting up your connection
type, have your account information from your ISP ready.

Select your connection type to proceed.

Figure 19 Connection Settings Screen

Select a DSL mode from the following:

Accessing the Setup Wizard 33

■ Dynamic IP Address, automatically allocating IP addresses for all

connected clients, see page 33

■ PPPoE — PPP over Ethernet, providing routing for multiple PCs, see

page 34

■ PPTP — Point-to-Point Tunneling Protocol , providing virtual private

networks, see page 36

■ Static IP Address, manually assigning IP addresses for clients, see

page 37

■ BigPond, Australia’s largest ISP, providing Internet access via ADSL/2+,

Cable, Next G, and Dial-up. page 37

and click Next.

For further information on selecting a mode see “WAN Settings” on

page 43

.

Dynamic IP Address Mode (For Multiple PCs)

You can configure the Router to obtain an IP address automatically from a
DHCP server.

34 CHAPTER 4: RUNNING THE SETUP WIZARD

Figure 20 Dynamic IP Address Screen

If the ISP requires you to input a Host Name, type it in the Host Name
field. The MAC Address field will be filled automatically.

Check all of your settings.

Click NEXT to proceed or BACK to change your settings.

PPPoE Mode

To set up the Router for use with a PPP over Ethernet (PPPoE) connection,
use the following procedure:

Figure 21 PPPoE Mode Screen

Accessing the Setup Wizard 35

1 Enter your user name in the User name field.

2 Enter your password in the Password field.

3 Re-type your password in the Please retype your password field.

4 If your ISP has provided you with a Service Name enter it in the Service

Name field, otherwise, leave it blank.

5 Leave the Maximum Transmission Unit (MTU) at the default value (1492)

unless you have a particular reason to change it.

36 CHAPTER 4: RUNNING THE SETUP WIZARD

6 Enter the Maximum Idle Time for the Internet connection. After this time

has been exceeded the connection will be terminated. Check Keep
session to keep the session alive. Check the Auto-connect check box to

automatically re-establish the connection as soon as you attempt to
access the Internet again. Check the Manual-connect check box to
manually re-establish the connection.

7 Check all of your settings.

8 Click NEXT to proceed or BACK to change your settings.

PPTP Mode

To set up the Router for use with a PPTP connection, use the following
procedure:

Figure 22 PPTP Mode Screen

1 Enter the IP Address information required by your ISP in the appropriate

fields.

2 Enter the User ID and Password required by your ISP.

3 Enter the IP Address of the PPTP gateway as provided by your ISP

4 Enter the Idle Time Out for the Internet connection. This is the period of

time for which the connection to the Internet is maintained during
inactivity. The default setting is 10 minutes. If your ISP charges you by the
minute, you should change the Idle Time Out to one minute. After the

Accessing the Setup Wizard 37

Idle Time Out has expired, set the action you wish the Router to take. You
can tell the device to connect manually or automatically as soon as you
try to access the Internet again, or to keep the session alive.

5 Check all of your settings.

6 Click NEXT to proceed or BACK to change your settings.

Static IP Address Mode (For Multiple PCs)

If your Service Provider has assigned a fixed IP address, enter the assigned
IP address information on the screen.

Figure 23 Static IP Address Screen

To assign a fixed IP address:

1 Enter your Internet IP address in the IP address field.

2 Enter the subnet mask in the Subnet Mask field.

3 Enter the default gateway IP address in the Gateway IP Address field.

4 Check all of your settings.

5 Click NEXT to proceed or BACK to change your settings.

BigPond (Australia)

BigPond is a service provider in Australia that uses a heartbeat system to
maintain the Internet connection.

38 CHAPTER 4: RUNNING THE SETUP WIZARD

To set up the Router for use with BigPond connection, use the following
procedure:

Figure 24 BigPond Mode Screen

1 Enter your user name in the User name field.

2 Enter your password in the Password field.

3 Re-type your password in the Please retype your password field.

4 Enter the Service Name provided by your ISP in the Authentication Service

Name field.

5 Check all of your settings.

6 Click NEXT to proceed or BACK to change your settings.

Your Router is now configured and ready for use.

See Chapter 5

for a detailed description of the Router configuration.

5

CONFIGURING THE ROUTER

Navigating Through the Router Configuration screens

Main Menu Clicking the Home button at any time, returns you to this home page.

Network Settings

Status The Status screen displays WAN/LAN connection status, firmware and

This chapter describes all the screens available through the Router
configuration screens, and is provided as a reference. To get to the
configuration screens, enter the Router’s default IP in the location bar of
your browser. The default IP is http://192.168.1.1.

However, if you changed the Router LAN IP address during initial
configuration, use the new IP address instead. Enter your password to
login to the management interface. (The default password is admin).

The Home screen shows the current software information. The main
menu is located on the left side, as shown in Figure 25
on an item from the main menu, the corresponding screen will then
appear in the center.

hardware version numbers, as well as information on DHCP clients
connected to your network. You can also view the security Log. The
security file, logfile.log, may be saved by clicking Save and choosing a
location.

. When you click

40 CHAPTER 5: CONFIGURING THE ROUTER

Figure 25 Status Screen

■ Current Time: Displays the current time.

■ INTERNET: Displays WAN connection type and status.

■ Release: Click on this button to disconnect from the WAN.

■ Renew: Click on this button to establish a connection to the WAN.

■ Network (LAN): Displays system IP settings, as well as DHCP Server,

Firewall, UPnP and Wireless status.

Network Settings 41

■ INFORMATION: Displays the number of attached clients, the firmware

versions, the physical MAC address for each media interface and for
the Wireless 11g Router, as well as the hardware version and serial
number.

■ DHCP Client Log: Displays information on DHCP clients on your

network.

■ Security Log: Displays illegal attempts to access your network.

■ Save: Click on this button to save the security log file.

■ Clear: Click on this button to delete the access log.

■ Refresh: Click on this button to refresh the screen.

LAN Settings Your Router is equipped with a DHCP server that will automatically assign

IP addresses to each computer on your network. The factory default
settings for the DHCP server will work with most applications. If you need
to make changes to the settings, you can do so.

The LAN settings screen allows you to:

■ Change the default IP address of the Router. The default IP is

192.168.1.1

■ Change the Subnet Mask. The default setting is 255.255.255.0

■ Enable/Disable the DHCP Server Function. The default is Enabled.

■ Specify the Starting and Ending IP Pool address. The default is

Starting: 2 / Ending: 254.

■ Specify the IP address Lease Time. The default is One Day.

■ Specify a local Domain Name.

The Router will also provide a list of all client computers connected to the
Router.

42 CHAPTER 5: CONFIGURING THE ROUTER

LAN Settings

The LAN Settings screen is used to specify the LAN IP address of your
Router, and to configure the DHCP server.

Figure 26 LAN Settings Screen

1 Enter the Router’s IP Address and Subnet Mask in the appropriate fields.

The default IP address is 192.168.1.1.

2 If you want to use the Router as a DHCP Server, select Enabled in the

DHCP Server field.

3 Enter the IP address range of Start IP and End IP in the IP Address Pool

fields.

4 Specify the Local Domain Name for your network (this step is optional).

5 Specify the DHCP Lease time by selecting the required value from the

Lease Time drop-down menu. The lease time is the length of time the
DHCP server will reserve the IP address for each computer.

6 Check all of your settings, and then click SAVE SETTINGS.

Network Settings 43

WAN Settings Specify the WAN connection type required by your Internet Service

Provider.

You should see the first entry already contains information that’s been
configured using the Setup Wizard in the initial setup. If you want to
change that information or set up other connection, select your
connetion type and click Next to set the detailed settings.

There are five options available for the DSL connection mode:

■ Dynamic IP Mode (for multiple PCs) (see page 43)

■ PPPoE — PPP over Ethernet, providing routing for multiple PCs (see

page 44

■ PPTP — PPP, providing routing for multiple PCs (see page 45)

■ Static IP Mode (for multiple PCs) (see page 46)

■ BigPond — providing Internet access for Australian users (see

page 47

)

)

Dynamic IP (For Multiple PCs)

To configure the Dynamic IP Address function correctly, you should obtain
the information on this screen from your ISP.

Figure 27 Dynamic IP Mode Screen

44 CHAPTER 5: CONFIGURING THE ROUTER

1 The Host name is optional, but may be required by some Service

Provider’s. Enter the host name in the Host Name field.

2 If required by your Service Provider, you can use the Clone MAC Address

button to copy the MAC address of the Network Interface Card (NIC)
installed in your PC to replace the WAN MAC address.

3 If necessary, you can use the Renew button on the Status page to renew

the WAN IP address.

4 Click SAVE SETTINGS.

PPPoE

PPP over Ethernet, provides routing for multiple PCs. To configure this
function correctly, you should obtain the information from your ISP.

Figure 28 PPPoE Settings Screen

1 Enter the user name assigned to you by your ISP in the User name field.

And enter the password assigned to you by your ISP in the Password field.
Re-enter your password in the Please retype your password field.

2 If your ISP has provided you with a Service Name enter it in the Service

Name field, otherwise, leave it blank.

3 Enter the Maximum Transmission Unit (MTU) value supplied by your ISP. If

you do not know this, leave it at the default value.

Network Settings 45

4 Enter a Maximum Idle Time (in minutes) to define a maximum period of

time for which the Internet connection is maintained during inactivity. If
the connection is inactive for longer than the Maximum Idle Time, then it
will be dropped.

5 Check Keep session to keep the session alive. Check the Auto-connect

checkbox to automatically re-establish the connection as soon as you
attempt to access the Internet again. Check the Manual-connect
checkbox to manually re-establish the connection

6 Click SAVE SETTINGS.

PPTP

PPTP is a popular choice among European DSL providers. To configure this
function correctly, you should obtain the information from your ISP.

Figure 29 PPTP Settings Screen

1 Enter the IP Address information required by your ISP in the appropriate

fields.

2 Enter the User ID assigned to you by your ISP in the User ID field. And

enter the password assigned to you by your ISP in the Password field.

3 Enter the IP Address of the PPTP gateway as provided by your ISP

4 Enter the Idle Time Out for the Internet connection. This is the period of

time for which the connection to the Internet is maintained during
inactivity. The default setting is 10 minutes. If your ISP charges you by the

46 CHAPTER 5: CONFIGURING THE ROUTER

minute, you should change the Idle Time Out to one minute. After the
Idle Time Out has expired, set the action you wish the Router to take. You
can tell the device to connect manually or automatically as soon as you
try to access the Internet again, or to keep the session alive.

5 Click SAVE SETTINGS.

Static IP (For Multiple PCs)

To configure the Static IP Address mode correctly, you should obtain the
information on this screen from your ISP.

Figure 30 Static IP Address Mode Screen

1 If your Service Provider has assigned a fixed IP address, enter the assigned

IP address, subnet mask and the gateway address into the provided fields.

2 Click SAVE SETTINGS.

Network Settings 47

BigPond

BigPond is a service provider in Australia that uses a heartbeat system to
maintain the Internet connection.

Figure 31 BigPond Mode Screen

1 Configure the built-in client with your user name, password and service

name to get online.

2 Click SAVE SETTINGS.

48 CHAPTER 5: CONFIGURING THE ROUTER

Wireless The Wireless Settings screens allow you to turn on/ turn off the wireless

function, and set up basic wireless settings.

You can enable or disable the wireless connection for your LAN. When
disabled, no wireless PCs can gain access to either the Internet or other
PCs on your wired or wireless LAN through this Router.

Figure 32 Wireless Settings Screen

To use the wireless feature, check the Enable checkbox and click SAVE
SETTINGS. After clicking SAVE SETTINGS, you will be asked to log in
again.

There are five items available:

■ Channel and SSID

■ Wireless Security

■ Access Control

■ 802.1X

■ WDS

Network Settings 49

Channel and SSID

Enter your wireless network settings on this screen. You must specify a
common radio channel and SSID (Service Set ID) to be used by the Router
and all of its wireless clients. Be sure you configure all of its clients to the
same value. For security purposes, you should change the default SSID
immediately.

Figure 33 Channel and SSID Screen

To set up the wireless channel and SSID:

1 Specify the SSID to be used by your wireless network in the SSID field. If

there are other wireless networks in your area, you should give your
wireless network a unique name.

2 Enable or disable Broadcast Wireless Network Name.

A feature of many wireless network adapters is that a computer's SSID
can be set to ANY, which means it looks randomly for any existing
wireless network. The available networks are then displayed in a site
survey, and your computer can select a network. By clicking Disable, you
can block this random search, and set the computer’s SSID to a specific
network (for example, WLAN). This increases network security. If you
decide to enable Broadcast Wireless Network Name, ensure that you
know the name of your network first.

3 Select whether your Router will operate in 11b mode only, 11g mode

only, or mixed 11b and 11g from the Wireless Mode drop-down menu.

50 CHAPTER 5: CONFIGURING THE ROUTER

4 Select the wireless channel you want to use from the Wi-Fi Channel

number drop-down menu.

5 Enabling Extend Range extends the wireless radio range of the Router.

6 Click SAVE SETTINGS.

Wireless Security

This feature prevents any non-authorized party from reading or changing
your data over the wireless network.

Figure 34 Wireless Security Screen

Select the wireless security mode that you want to use from the
drop-down menu, and click SAVE SETTINGS. There are three selections:

■ No WEP, No WPA/WPA2 (see page 51)

■ WEP Only (see page 51)

■ WPA/WPA2 (see page 52)

Network Settings 51

No WEP, No WPA/WPA2 In this mode, wireless transmissions will not
be encrypted, and will be visible to everyone. However, when setting up
or debugging wireless networks, it is often useful to use this security
mode.

WEP Only WEP is the basic mechanism to transmit your data securely
over the wireless network. Matching encryption keys must be setup on
your Router and wireless client devices to use WEP.

Figure 35 WEP Only Screen

To enable 64-bit WEP:

1 You can enter the 64-bit WEP key manually:

■ enter the WEP key as 5 pairs of hex digits (0-9, A-F).

Or you can generate the 64-bit WEP key automatically:

■ enter a memorable passphrase in the Passphrase box to generate a

hex key automatically from the passphrase.

52 CHAPTER 5: CONFIGURING THE ROUTER

For 64-bit WEP, you can enter up to four keys, in the fields Key 1 to Key 4.
The radio button on the left hand side selects the key that is used in
transmitting data.

Note that all four WEP keys on each device in the wireless network must
be identical.

2 Click SAVE SETTINGS.

To enable 128-bit WEP:

1 You can enter the 128-bit WEP key manually:

■ enter your WEP key as 13 pairs of hex digits (0-9, A-F).

Or you can generate the 128-bit WEP key automatically:

■ enter a memorable passphrase in the Passphrase box to generate a

hex key automatically from the passphrase.

The WEP keys on each device on the wireless network must be identical.

In 128-bit WEP mode, only one WEP key can be specified.

2 Click SAVE SETTINGS.

WPA/WPA2 Only WPA (Wi-Fi Protected Access) provides dynamic key
changes and constitutes the best security solution. If your network does
not have a RADIUS server. Select the no server option.

Network Settings 53

Figure 36 WPA/WPA2 Only Screen

1 Select WPA/WPA2 Only from the Security Mode drop-down menu.

2 Select Encryption technique from the drop-down menu, two options are

available: TKIP+AES (WPA/WPA2) or AES WPA2 Only.

3 Select 802.1X or Pre-shared Key for the authentication method.

■ 802.1X: for the enterprise network with a RADIUS server.

■ Pre-shared key: for the SOHO network environment without an

authentication server.

4 Select the key type to be used in the Pre-shared Key.

5 Type the key in the Pre-shared Key field.

6 Set the period of renewing the broadcast/multicast key in the Group Key

Re_Keying field.

7 Click SAVE SETTINGS.

54 CHAPTER 5: CONFIGURING THE ROUTER

Access Control

This feature is used to filter the clients based on their MAC addresses.

Check the Enable MAC Address Filtering checkbox on the Access Control
screen.

Figure 37 Access Control Screen

There are two options available in the Access rule for registered MAC
address field:

■ if you click Allow, this means only the MAC addresses registered here

in the list will be allowed to access the Router via wireless link.

■ if you click Deny, this means the registered MAC addresses will not be

able to access the Router via wireless link.

Use the MAC Address Filtering List to quickly copy the MAC addresses of
the current wireless clients into the list table. You can define up to 32
MAC addresses to the list.

You can click Clear to delete the current entry in the list.

Network Settings 55

802.1X

If 802.1X is used in your network, then you should enable this function
for the Router. 802.1X is a method of authenticating a client wireless
connection. Enter the parameters below to connect the Router to the
Authentication Server.

Figure 38 802.1X Screen

■ 802.1X Authentication

Enable or disable the authentication function.

■ Session Idle Timeout

This is the time (in seconds) that a session will sit inactive before
terminating. Set to 0 if you do not want the session to timeout.
(Default: 300 seconds)

■ Re-Authentication Period

The interval time (in seconds) after which the client will be asked to
re-authenticate. For example, if you set this to 30 seconds, the client
will have to re-authenticate every 30 seconds. Set to 0 for no
re-authentication. (Default: 3600 seconds)

■ Quiet Period

This is the interval time (in seconds) for which the Router will wait
between failed authentications. (Default: 60 seconds)

■ Server Type

Sets the authentication server type.

56 CHAPTER 5: CONFIGURING THE ROUTER

■ RADIUS Server Parameters

■ Server IP

Set the IP address of your RADIUS server.

■ Server Port

Set the connection port that is configured on the radius server.

■ Secret Key

The 802.1x secret key used to configure the Wireless 11g Router.

■ NAS-ID

Defines the request identifier of the Network Access Server.

The use of IEEE 802.1X offers an effective framework for authenticating
and controlling user traffic to a protected network, as well as dynamically
varying encryption keys. 802.1X ties EAP (Extensible Authentication
Protocol) to both the wired and wireless LAN media and supports multiple
authentication methods, such as token cards, Kerberos, one-time
passwords, certificates, and public key authentication.

Click SAVE SETTINGS.

Firewall 57

WDS

The Router supports WDS (Wireless Distribution System). WDS enables
one or more Access Points to rebroadcast received signals to extend
range and reach, though this can affect the overall throughput of data.

Figure 39 WDS Settings Screen

1 Check the Enable WDS Features checkbox.

2 To refresh the list of available access points, click Scan.

3 Check the Enable WDS checkbox of the appropriate access points.

(Default: Disable)

WDS implementation varies from vendor to vendor. Hence there’s no
assured WDS interoperability with between all devices in the market.

Firewall From these screens, you can configure settings for the firewall.

Your Router is equipped with a firewall that will protect your network
from a wide array of common hacker attacks including Ping of Death
(PoD) and Denial of Service (DoS) attacks. You can turn the firewall
function off if needed. Turning off the firewall protection will not leave
your network completely vulnerable to hacker attacks, but 3Com
recommends that you leave the firewall enabled whenever possible.

58 CHAPTER 5: CONFIGURING THE ROUTER

Figure 40 Firewall Screen

The firewall does not significantly affect system performance, so we
advise leaving it enabled to protect your network.

Enable the firewall feature, and click SAVE SETTINGS to proceed.

Schedule Rule The Router can be configured to restrict access to the Internet, email or

other network services at specific days and times. Each access control rule
may be activated at a scheduled time. First, define the schedule time on
the Schedule Rule page, then apply the rule on the Access Control screen
(see page 60

).

Firewall 59

Figure 41 Schedule Rule Screen

1 Click Add Schedule Rule to add a schedule rule (a screen similar to

Figure 42

will appear).

Figure 42 Add Schedule Rule Screen

2 Enter a name and comment for the schedule rule in the Name and

Comment fields.

60 CHAPTER 5: CONFIGURING THE ROUTER

3 Specify the schedule rules for the required days and times - note that all

times should be in 24 hour format.

4 Click OK and SAVE SETTINGS.

Access Control The Router can be configured to restrict access to the Internet, email or

other network services at specific days and times. Restriction can be set
for a single computer, a range of computers, or multiple computers.

You can define the traffic type permitted or not-permitted to the Internet.

Figure 43 Access Control Screen

To edit or delete specific existing filtering rules, click on Edit or Delete for
the appropriate filtering rule.

To configure a new filtering rule:

1 Check the Enable Filtering Function checkbox.

2 Click Add PC (a screen similar to Figure 44

will appear).

Figure 44 Access Control Add PC Screen

Firewall 61

3 Enter a description in the Client PC Description field, and the IP address or

IP address range into the Client PC IP Address fields.

4 Select the services to be blocked. A list of popular services is given on this

screen, to block a particular service, check the appropriate Blocking
checkbox.

If the service to be restricted is not listed here, you can enter a custom
range of ports at the bottom of the screen, under User Defined Service.

62 CHAPTER 5: CONFIGURING THE ROUTER

5 If you want the restriction to apply only at certain times, select the

schedule rule to apply from the Schedule Rule drop-down menu.

Note that schedule rules are defined on the Schedule Rules screen
(see page 58

6 Click OK to add the settings.

MAC Filter Use the MAC Filtering to block access to your network using MAC

addresses.

Figure 45 MAC Filter Screen

).

The Router can also limit the access of hosts within the local area network
(LAN). The MAC Filtering Table allows the Router to enter up to 32 MAC
addresses that are allowed access to the WAN port. All other devices will
be denied access. By default, this feature is disabled.

Firewall 63

URL Filtering To configure the URL filtering feature, use the table on the URL Filtering

screen to specify the Web sites (www.somesite.com) and/or keywords
you want to filter on your network. This feature can be used to protect
children from accessing violent or pornographic web sites.

For example, entering a keyword of xxx would block access to any URL
that contains the string xxx.

Figure 46 URL Filtering Screen

Enter the URL address or keywords in the URL/Keyword field. You can
define up to 30 sites or keywords here.

To complete this configuration, you will need to create or modify an
access rule in "Access Control Add PC" on page 60

. To modify an
existing rule, click the Edit option next to the rule you want to modify. To
create a new rule, click on the Add PC option.

From the Access Control, Add PC section, check the option for WWW
with URL Filtering in the Client PC Service table to filter out the web sites
and keywords selected below, on a specific PC.

64 CHAPTER 5: CONFIGURING THE ROUTER

Intrusion Detection The Router’s firewall inspects packets at the application layer, maintains

TCP and UDP session information including timeouts and number of
active sessions, and provides the ability to detect and prevent certain
types of network attacks such as Denial-of-Service (DoS) attacks.

Figure 47 Intrusion Detection Screen

Firewall 65

Network attacks that deny access to a network device are called DoS
attacks. DoS attacks are aimed at devices and networks with a
connection to the Internet. Their goal is not to steal information, but to
disable a device or network so users no longer have access to network
resources.

The Router protects against DoS attacks including: Ping of Death (Ping
flood) attack, SYN flood attack, IP fragment attack (Teardrop Attack),
Brute-force attack, Land Attack, IP Spoofing attack, IP with zero length,
TCP null scan (Port Scan Attack), UDP port loopback, Snork Attack.

The firewall does not significantly affect system performance, so we
advise enabling the prevention features to protect your network.

66 CHAPTER 5: CONFIGURING THE ROUTER

Tab le 3 Intrusion Detection Parameters

Parameter Defaults Description

ntrusion Detection Feature

SPI and Anti-DoS
firewall
protection

RIP Defect Disabled If the router does not reply to an IPX RIP request

Discard Ping to
WAN

Stateful Packet
Inspection

Yes The Intrusion Detection feature of the Router

limits the access of incoming traffic at the WAN
port. When the Stateful Packet Inspection (SPI)
feature is turned on, all incoming packets are
blocked except those types marked with a check
in the SPI section at the top of the screen.

packet, it will stay in the input queue and not be
released. Accumulated packets could cause the
input queue to fill, causing severe problems for all
protocols. Enabling this feature prevents the
packets accumulating.

Don’t
discard

Enabled This option allows you to select different

Prevents a ping on the Router’s WAN port from
being routed to the network.

application types that are using dynamic port
numbers. If you wish to use Stateful Packet
Inspection (SPI) for blocking packets, click on the
Yes radio button in the “Enable SPI and Anti-DoS
firewall protection” field and then check the
inspection type that you need, such as Packet
Fragmentation, TCP Connection, UDP Session,
FTP Service and TFTP Service.

It is called a “stateful” packet inspection because
it examines the contents of the packet to
determine the state of the communication; i.e., it
ensures that the stated destination computer has
previously requested the current communication.
This is a way of ensuring that all communications
are initiated by the recipient computer and are
taking place only with sources that are known
and trusted from previous interactions. In
addition to being more rigorous in their
inspection of packets, stateful inspection firewalls
also close off ports until a connection to the
specific port is requested.

When particular types of traffic are checked, only
the particular type of traffic initiated from the
internal LAN will be allowed. For example, if the
user only checks FTP Service in the Stateful Packet
Inspection section, all incoming traffic will be
blocked except for FTP connections initiated from
the local LAN.

Firewall 67

Parameter Defaults Description

When hackers attempt to enter your network, we can alert you by email

Your E-mail
Address

SMTP Server
Address

POP3 Server
Address

User Name Enter your email account user name.

Password Enter your email account password.

Connection Policy

Fragmentation
half-open wait

TCP SYN wait 30 secs Defines how long the software will wait for a TCP

TCP FIN wait 5 secs Specifies how long a TCP session will be

TCP connection
idle timeout

UDP session idle
timeout

DoS Detect Criteria

Total incomplete
TCP/UDP sessions
HIGH

Total incomplete
TCP/UDP sessions
LOW

Incomplete
TCP/UDP sessions
(per min.) HIGH

Incomplete
TCP/UDP sessions
(per min.) LOW

10 secs Configures the number of seconds that a packet

3600 secs
(1 hour)

30 secs The length of time for which a UDP session will

300
sessions

250
sessions

250
sessions

200
sessions

Enter your email address.

Enter your SMTP server address (usually the part
of the email address following the “@” sign).

Enter your POP3 server address (usually the part
of the email address following the “@” sign).

state structure remains active. When the timeout
value expires, the router drops the unassembled
packet, freeing that structure for use by another
packet.

session to reach an established state before
dropping the session.

managed after the firewall detects a
FIN-exchange.

The length of time for which a TCP session will be
managed if there is no activity.

be managed if there is no activity.

Defines the rate of new unestablished sessions
that will cause the software to start deleting
half-open sessions.

Defines the rate of new unestablished sessions
that will cause the software to stop deleting
half-open sessions.

Maximum number of allowed incomplete
TCP/UDP sessions per minute.

Minimum number of allowed incomplete
TCP/UDP sessions per minute.

68 CHAPTER 5: CONFIGURING THE ROUTER

Parameter Defaults Description

Maximum
incomplete
TCP/UDP sessions
number from
same host

Incomplete
TCP/UDP sessions
detect sensitive
time period

Maximum
half-open
fragmentation
packet number
from same host

Half-open
fragmentation
detect sensitive
time period

Flooding cracker
block time

30
sessions

900 msecs Length of time before an incomplete TCP/UDP

30
sessions

1 sec Length of time before a half-open fragmentation

300 secs Length of time from detecting a flood attack to

Maximum number of incomplete TCP/UDP
sessions from the same host.

session is detected as incomplete.

Maximum number of half-open fragmentation
packets from the same host.

session is detected as half-open.

blocking the attack.

We do not recommend modifying the default parameters shown above.

Firewall 69

DMZ If you have a client PC that cannot run an Internet application properly

from behind the firewall, you can open the client up to unrestricted
two-way Internet access. This may be necessary if the NAT feature is
causing problems with an application such as a game or video
conferencing application.

Figure 48 DMZ Screen

Enter the IP address of a DMZ (Demilitarized Zone) host on this screen.
Adding a client to the DMZ may expose your local network to a variety of
security risks, so only use this option as a last resort

70 CHAPTER 5: CONFIGURING THE ROUTER

Maintenance These screens allow you to manage different parameters of the Router

and perform certain administrative functions.

Configuration Tools Use this configuration screen to backup, restore or reset the

configuration details of the Router.

Figure 49 Configuration Tools Screen

■ Backup Wireless Router Configuration — You can save your current

configuration by clicking the Backup Wireless Router Configuration
button. Saving your configuration will allow you to restore it later if
your settings are lost or changed. It is recommended that you backup
your current configuration before performing a firmware update.

■ Restore from saved Configuration file (backup.bin) — The restore

option will allow you to restore a previously saved configuration.
Check the Restore from saved Configuration file radio button and
click NEXT to restore the saved backup configuration file.

■ Restore Wireless Router to Factory Defaults — Using this option will

reset all of the settings in the Router to the factory default settings. It
is recommended that you backup your settings before you restore all
of the defaults. To restore the factory default settings, check Restore
Wireless Router to Factory Defaults and click NEXT. You will be asked
to confirm your decision.

Maintenance 71

Firmware Upgrade From time to time 3Com may release new versions of the Router’s

firmware. Firmware updates contain improvements and fixes to problems
that may have existed.

Figure 50 Firmware Upgrade Screen

Please download the firmware file to your PC first, and then click Browse
and select the firmware file. Click BEGIN UPGRADE to upload the
firmware to the Router.

72 CHAPTER 5: CONFIGURING THE ROUTER

Restart Router Sometimes it may be necessary to restart (or reboot) the Router.

Restarting the Router from this screen will not delete any of your
configuration settings.

Figure 51 Reboot Screen

Click the Reboot Wireless Router button to restart the Router.

Advanced Settings From the Advanced Settings screen, you can configure:

■ NAT: Shares a single ISP account with multiple users, sets up virtual

servers.

■ System: Sets the local time zone, the password for administrator

access, the IP address of a PC that will be allowed to manage the
Router remotely, and the IP address of a Domain Name Server.

■ UPnP: Universal Plug and Play (UPnP) allows for simple and robust

connectivity between external devices and your PC.

■ DNS: Specify the IP address of your network domain name server.

■ DDNS: Configures Dynamic DNS function.

■ Routing: Sets routing parameters and displays the current routing

table.

Advanced Settings 73

NAT The first menu item in the Advanced Settings section is Network Address

Translation (NAT). This process allows all of the computers on your home
network to use one IP address. Using the NAT capability of the Router,
you can access the Internet from any computer on your home network
without having to purchase more IP addresses from your ISP.

Figure 52 NAT Screen

To use the NAT feature:

1 Check the Enable radio button.

2 Click SAVE SETTINGS.

74 CHAPTER 5: CONFIGURING THE ROUTER

Address Mapping

Network Address Translation (NAT) allows IP addresses used in a private
local network to be mapped to one or more addresses used in the public,
global Internet.

Figure 53 Address Mapping Screen

This feature limits the number of public IP addresses required from the ISP
and also maintains the privacy and security of the local network. We
allow one public IP address to be mapped to a pool of local addresses.

Virtual Servers

The Virtual servers feature allows you to route external (Internet) calls for
services such as a web server (port 80), FTP server (Port 21), or other
applications through your Router to your internal network. Since your
internal computers are protected by a firewall, machines from the
Internet cannot get to them because they cannot be ‘seen’.

If you need to configure the Virtual Server function for a specific
application, you will need to contact the application vendor to find out
which port settings you need.

The maximum number of virtual servers that can be configured is 20.

Advanced Settings 75

Figure 54 Virtual Servers Screen

A list of popular servers has been included to choose from. Select the
server from the Popular servers drop-down menu. Then click Add, your
selection will be added to the table.

If the server that you want to use is not listed in the drop-down menu,
you can manually add the virtual server to the table.

To manually configure your virtual servers:

1 Enter the IP address, and the description in the spaces provided for the

internal machine.

2 Select the protocol type (TCP, UDP, or both TCP and UDP) from the

drop-down menu.

3 Specify the public port that will be seen by clients on the Internet, and the

LAN port which the traffic will be routed to.

4 You can enable or disable each Virtual Server entry by by checking or

unchecking the appropriate Enable checkbox.

5 Click Add or Clean button to save the changes for each Virtual Server

entry.

76 CHAPTER 5: CONFIGURING THE ROUTER

Special Applications

Some applications, such as Internet gaming, video-conferencing, Internet
telephony and others, require multiple connections. These applications
cannot work with Network Address Translation (NAT) enabled. If you
need to run applications that require multiple connections, use the
following screen to specify the additional public ports to be opened for
each application.

Figure 55 Special Applications Screen

To put a computer in the DMZ:

1 Click the List of well known special applications link for more

information.

2 Specify the public port number normally associated with an application in

the Trigger Port field. Set the protocol type to TCP or UDP, then enter the
ports that the application requires. The ports may be in the format of a
single port, or in a range, e.g., 72-96, or a combination of both.

3 Popular applications requiring multiple ports are listed in the Popular

Applications field. From the drop-down list, choose the application and
then choose a row number to copy this data into.

4 Click SAVE SETTINGS.

Choosing a row that already contains data will overwrite the current
settings.

Advanced Settings 77

For a full list of ports and the services that run on them, see
www.iana.org/assignments/port-numbers

NAT Mapping Table

This page displays the current NAPT (Network Address Port Translation)
address mappings.

Figure 56 NAT Mapping Table Screen

The NAT address mappings are listed 20 lines per page, click the control
buttons to move forwards and backwards. As the NAT mapping is
dynamic, a Refresh button is provided to refresh the NAT Mapping Table
with the most updated values.

The content of the NAT Mapping Table is described as follows:

■ Protocol - protocol of the flow.

■ Local IP - local (LAN) host's IP address for the flow.

■ Local Port - local (LAN) host's port number for the flow.

■ Pseudo IP - translated IP address for the flow.

■ Pseudo Port - translated port number for the flow.

■ Peer IP - remote (WAN) host's IP address for the flow.

■ Peer Port - remote (WAN) host's port number for the flow.

78 CHAPTER 5: CONFIGURING THE ROUTER

System This section includes all the basic configuration tools for the Router, such

as time settings, password settings, remote management and Syslog
server setup.

Time Zone

You can set the time settings for the Router on this screen.

Figure 57 Time Zone Screen

Advanced Settings 79

The Router keeps time by connecting to a Network Time Protocol (NTP)
server. This allows the Router to synchronize the system clock to the
Internet. The synchronized clock in the Router is used to record the
security log and control client filtering. Select the time zone that you
reside in. If you reside in an area that observes Daylight Saving, then
check the checkbox for Enable Daylight Savings. The system clock may
not update immediately. Allow at least 15 minutes for the Router to
contact the time servers on the Internet and get a response. You cannot
set the clock yourself.

You can specify which NTP servers the Router will use to update the
system clock, although doing this should only be necessary if you are
experiencing difficulty.

Password Settings

Use this page to restrict access based on a password. For security you
should assign one before exposing the Router to the Internet.

Figure 58 Password Settings Screen

Passwords can contain from 3 to12 alphanumeric characters and are case
sensitive.

80 CHAPTER 5: CONFIGURING THE ROUTER

If your password is lost, or you cannot gain access to the user interface,
press the reset button on the bottom of the device (holding it down for at
least eight seconds) to restore the factory defaults. The default password
is “admin”.

Enter a maximum Idle Time Out (in minutes) to define a maximum period
of time an inactive login session will be maintained. If the connection is
inactive for longer than the maximum idle time, it will be logged out, and
you will have to log in to the web management system again. Setting the
idle time to 0, will mean the connection never times out. (Default:
10 minutes)

Remote Management

By default, management access is only available to users on your local
network. However, you can also manage the Router from a remote host
by entering the IP address of a remote computer on this screen.

Figure 59 Remote Management Screen

This feature allows you to make changes to your Router’s settings from
anywhere on the Internet. Four options are available:

■ If you do not want to use this feature, select Disable Remote

Administration.

■ Select Enable administration from a single Internet Host, and enter

the IP address, to allow only one computer to use the remote

Advanced Settings 81

administration. This is more secure, as only the specified IP address
will be able to manage the Router.

■ Select Enable administration from a whole Subnet Internet Host,

and enter the IP address and subnet mask, to allow PCs from that
specific subnet group to use the remote administration.

■ Select Enable administration from any Internet Host, this allows

any computer to access the Router remotely.

Before you enable this function, ensure that you have set the
Administration Password.

Click SAVE SETTINGS.

Syslog Server

Using third party syslog software, this Syslog Server tool will automatically
download the Router log to the specified server IP address.

Figure 60 Syslog Server Screen

1 Enter the Server LAN IP Address in the space provided.

2 Check the Enabled Syslog Server checkbox.

3 Click SAVE SETTINGS.

82 CHAPTER 5: CONFIGURING THE ROUTER

UPNP Universal Plug and Play technology makes home networking simple and

affordable. This architecture offers pervasive peer-to-peer network
connectivity of PCs of all form factors, intelligent appliances, and wireless
devices. UPnP architecture leverages TCP/IP and the web to enable
seamless proximity networking in addition to control and data transfer
among networked devices in the home, office, and everywhere in
between.

Figure 61 UPNP Screen

1 Click Enable to turn on the Universal Plug and Play function of the Router.

This function allows the device to automatically and dynamically join a
network.

2 Click SAVE SETTINGS.

Advanced Settings 83

DNS Domain Name Service (or Server) is an Internet service that translates

domain names into IP addresses. Because domain names are alphabetic,
they’re easier to remember. The Internet however, is really based on IP
addresses. Every time you use a domain name, a DNS service must
translate the name into the corresponding IP address. For example, the
domain name www.example.com might translate to 198.105.232.4.

Check with your ISP for information on this screen.

Figure 62 DNS Screen

If your ISP provided you with specific DNS addresses to use, enter them
into the appropriate fields on this screen and click SAVE SETTINGS.

Many ISPs do not require you to enter this information into the Router. If
you are using a Static IP connection type, you may need to enter a
specific DNS address and secondary DNS address for your connection to
work properly. If your connection type is Dynamic, PPTP or PPPoE, it is
likely that you do not have to enter a DNS address.

84 CHAPTER 5: CONFIGURING THE ROUTER

DDNS The Router provides a list of dynamic DNS providers for you to choose

from. Dynamic Domain Name Server (DDNS) enables you to map a static
domain name to a dynamic IP address.

The Router supports two DDNS providers:

■ DynDNS.org

■ TZO.com

Before you set up DDNS, you must obtain an account, password or key
and static domain name from your DDNS provider.

DDNS is disabled by default.

Figure 63 Dynamic Domain Name Server (DDNS) Screen

1 Check Enable Dynamic DNS.

2 Select the provider, and then enter the necessary information provided by

your DDNS provider.

3 Click SAVE SETTINGS.

Advanced Settings 85

Routing This section defines routing related parameters, including static routes,

RIP (Routing Information Protocol) parameters and routing table.

Static Routes You can configure static routes in this screen.

To add a static route entry to the table, click Add. To change an existing
entry, click Edit. To delete an entry, click Delete.

Figure 64 Static Routes Screen

This screen shows a list of current static route entries. For each entry, the
following information is displayed:

■ Index — the index of the entry.

■ Network Address — the network address of the route.

■ Subnet Mask — the subnet mask of the route.

A network address of 0.0.0.0 and a subnet mask of 0.0.0.0 indicates the
default route.

■ Gateway — the router used to route data to the network specified by

the network address.

■ Configure — Allows you to edit existing routes.

After you have finished making changes to the table, click SAVE
SETTINGS.

86 CHAPTER 5: CONFIGURING THE ROUTER

RIP RIP (Routing Information Protocol) - RIP allows the network administrator

to set up routing information on one RIP-enabled device and send that
information to all RIP-enabled devices on the network.

Figure 65 RIP Parameter Screen

You can set up RIP independently on both LAN and WAN interfaces.

1 Check the Enable RIP Mode checkbox.

2 Check the Enable Auto summary checkbox. Auto summarization sends

simplified routing data to other RIP-enabled devices rather than full
routing data.

3 Select the Operation Mode:

■ Disabled — RIP is not enabled for the WAN or LAN interface.

■ Enabled — RIP is enabled for the WAN or LAN interface. The router

will transmit RIP update information to other RIP-enabled devices.

■ Silent — RIP is enabled, however the Router only receives RIP update

messages, it will not transmit any messages itself.

4 In the Version field, select 1 or 2.

3Com recommends that you only use RIPv1 if there is an existing
RIP-enabled device on your network that does not support RIPv2. In all
other cases, you should use RIPv2.

Advanced Settings 87

5 Use the Poison Reverse drop-down menu to enable or disable Poison

Reverse on the Router. Enabling Poison Reverse on your Router allows it

to indicate to other RIP-enabled devices that they have both routes that
point to each other, preventing data loops.

6 Use the Authentication Required field to choose the mode of

authentication:

■ None — Switches off authentication on the specified interface.

■ Password — An unencrypted text password that needs to be set on all

RIP-enabled devices connected to this Router. RIP information is not
shared between devices whose passwords do not match.

7 In the Authentication Code field, enter the password that is required if

the Password option has been selected.

8 Click SAVE SETTINGS.

Routing Table This screen displays details for the default routing used by your Router

and any routing created using Static Routing or RIP.

Figure 66 Routing Table Screen

88 CHAPTER 5: CONFIGURING THE ROUTER

6

TROUBLESHOOTING

Basic Connection Checks

Browsing to the Router Configuration Screens

■ Check that the Router is connected to your computers and to the

telephone line, and that all the equipment is powered on. Check that
the LAN Status and LEDs on the Router are illuminated, and that any
corresponding LEDs on the NIC are also illuminated.

■ Ensure that the computers have completed their start-up procedure

and are ready for use. Some network interfaces may not be correctly
initialized until the start-up procedure has completed.

■ If the link status LED does not illuminate for a port that is connected,

check that you do not have a faulty cable. Try a different cable.

If you have connected your Router and computers together but cannot
browse to the Router configuration screens, check the following:

■ Confirm that the physical connection between your computer and the

Router is OK, and that the LAN Status LEDs on the Router and
network adapter are illuminated and indicating the same speed
(10Mbps or 100Mbps). Some NICs do not have status LEDs, in which
case a diagnostic program may be available that can give you this
information.

■ Ensure that you have configured your computer as described in

Chapter 3

to ensure that your computer receives an IP address.

. Restart your computer while it is connected to the Router

■ When entering the address of the Router into your web browser,

ensure that you use the full URL including the http:// prefix (e.g.
http://192.168.1.1).

■ Ensure that you do not have a Web proxy enabled on your computer.

Go to the Control Panel and click on Internet Options. Select the
Connections tab and click on the LAN Settings button at the bottom.
Make sure that the Proxy Server option is unchecked.

90 CHAPTER 6: TROUBLESHOOTING

■ If you cannot browse to the Router, use the winipcfg utility in

Windows 98/ME to verify that your computer has received the correct
address information from the Router. From the Start menu, choose
Run and then enter winipcfg. Check that the computer has an IP
address of the form 192.168.1.xxx (where xxx is in the range 2-254),
the subnet mask is 255.255.255.0, and the default Router is

192.168.1.1 (the address of the Router). If these are not correct, use
the Release and Renew functions to obtain a new IP address from the
Router. Under Windows 2000, Windows XP and Windows Vista, use
the ipconfig command-line utility to perform the same functions.

Connecting to the Internet

Forgotten Password and Reset to Factory Defaults

If you can browse to the Router configuration screens but cannot access
Web sites on the Internet, check the following:

■ Confirm that the physical connection between the Router and the

telephone line is OK, and that the WAN LED on the Router is
illuminated.

■ Ensure that you have entered the correct information into the Router

configuration screens as required by your Internet Service Provider. Use
the Internet Settings screen to verify this.

■ Check that the PPPoE or PPTP user name and password are correct.

■ Ensure that your computers are not configured to use a Web proxy.

On Windows computers, this can be found under Control Panel >
Internet Options > Connections.

If you can browse to the Router configuration screen but cannot log on
because you do not know or have forgotten the password, follow the
steps below to reset the Router to its factory default configuration.

CAUTION: All your configuration changes will be lost, and you will need
to run the configuration wizard again before you can re-establish your
Router connection to the Internet. Also, other computer users will lose
their network connections whilst this process is taking place, so choose a
time when this would be convenient.

1 Power off the Router.

2 Disconnect all your computers and the network line from the Router.

3 Re-apply power to the Router, and wait for it to finish booting up.

Wireless Networking 91

4 Press and hold the Reset button on the bottom of the device for

8 seconds.

5 The Router will restart, and when the start-up sequence has completed,

browse to:

http://192.168.1.1

and run the configuration wizard. You may need to restart your computer
before you attempt this.

6 When the configuration wizard has completed, you may reconnect your

network as it was before.

Wireless Networking

■ Ensure that you have an 802.11b or 802.11g wireless adapter for

each wireless computer, and that it is correctly installed and
configured. Verify that each wireless computer has either Windows 98
or higher or MAC OS 8.5 or higher.

■ Verify that your wireless computers are configured to work in

Infrastructure mode and not Ad Hoc mode. The Router contains an
Access Point that is designed to operate in Infrastructure mode. Ad
Hoc mode is not supported by the Router.

■ If you have a wired and a wireless NIC in the same computer, ensure

that the wired NIC is disabled.

■ Check the status of the WLAN LED, it should be lit if wireless is

enabled and will flash when there is wireless activity. If not lit go to

Wireless” on page 48 and enable wireless networking.

“

■ Ensure that the TCP/IP settings for all devices are correct.

■ Ensure that the Wireless Clients are using the same SSID or Service

Area Name as the Router. The SSID is case-sensitive.

■ Ensure that the encryption method and level that you use on your

clients are the same as those configured on the Router. The Router
cannot simultaneously support WPA and WEP encryption.

■ Ensure that you have the wireless computer enabled in the list of

allowed MAC addresses if you are using MAC Address Filtering on the
Router.

■ If you are having difficulty connecting or are operating at a low speed

try changing the antenna positions on the rear of the Router.
For more effective coverage you can try reorientating your Antenna.
Place one antenna vertically and one horizontally to improve coverage.

92 CHAPTER 6: TROUBLESHOOTING

■ Sources of interference: The 2.4Ghz ISM band is used for 802.11b and

■ Most wireless computer adapters will scan the channels for the

Additionally consider moving the wireless computer closer to the
Router to confirm that the building structure or fittings are not
adversely affecting the connectivity. If this resolves the problem
consider relocating the wireless computer or the Router, or trying a
different channel on the Router.

802.11g. This is generally a licence free band for low power
applications, and you may have other devices at your location that
operate in this frequency band. You should take care to ensure that
there are no devices, like microwave ovens for example, close to the
Router or wireless computers as this could affect receiver sensitivity
and reduce the performance of your network. If you are unsure try
relocating both the wireless computers and the Router to establish
whether this problem exists.

wireless Router. If a wireless computer has not located the Router then
try initiating a search manually if the client software supports this
feature or manually set the channel on your wireless computer to
correspond to the Router channel number. Please refer to your
wireless computer adapter documentation and vendor to do this.

■ Speed of connection: The 802.11b and 802.11g standards will

automatically choose the best speed depending on the quality of your
connection. As the signal quality weakens then the speed falls back to
a lower speed. The speeds supported by 802.11g are 54 Mbps,
48 Mbps, 36 Mbps, 24 Mbps, 18 Mbps, 12 Mbps and 6 Mbps. The
speeds supported by 802.11b are 11 Mbps, 5.5 Mbps, 2 Mbps and
1 Mbps. In general the closer you are to the Router the better the
speed. If you are not achieving the speed you had anticipated then try
moving the antenna on the Router or moving the wireless computer
closer to the Router. In an ideal network the Router should be located
in the centre of the network with wireless computers distributed
around it. Applications are generally available with the computer
wireless card to carry out a site survey. Use this application to find the
optimal siting for your wireless computer. Consult your Computer
Card documentation and vendor for more details.

Recovering from Corrupted Software 93

Recovering from Corrupted Software

If the system software has become corrupted, the Router will enter a
“recovery” state; DHCP is enabled, and the LAN IP address is set to

192.168.1.1. Follow the instructions below to upload a new copy of the
system software to a Router unit in this state.

Ensure that one of your computers has a copy of the new software image
file stored on its hard disk or available on CD-ROM.

Check on www.3com.com for the latest version of firmware.

1 Remove power from the Router and disconnect the telephone line and all

your computers, except for the one computer with the software image.

2 You will need to reconfigure this computer to obtain an IP address

automatically (see “

Obtaining an IP Address Automatically” on page 23).

3 Restart the computer, and re-apply power to the Router.

4 Using the Web browser on the computer, enter the following URL in the

location bar:

http://192.168.1.1.

This will connect you to the Recovery utility in the Router.

5 Follow the on-screen instructions. Enter the path and filename of the

software image file.

6 When the upload has completed, the Router will restart, run the self-test

and, if successful, resume normal operation.

7 Refer to the Installation Guide to reconnect your Router to the telephone

line and the computers in your network. Do not forget to reconfigure the
computer you used for the software upload.

If the Router does not resume normal operation following the upload, it
may be faulty. Contact your supplier for advice.

94 CHAPTER 6: TROUBLESHOOTING

Frequently Asked Questions

How do I reset the Router to Factory Defaults?

Forgotten Password and Reset to Factory Defaults” on

See “

page 90

.

How many computers on the LAN does the Router support?

A maximum of 253 computers on the LAN are supported.

How many wireless clients does the Router support?

A maximum of 32 wireless clients are supported.

Maximum practical number of users depends on speed of broadband
connection and amount of traffic generated by users.

There are only 4 LAN ports on the Router. How are additional
computers connected?

You can expand the number of connections available on your LAN
by using hubs, switches and wireless access points connected to
the Router. 3Com wireless access points and switches provide a
simple, reliable means of expanding your network; contact your
supplier for more information, or visit:

http://www.3com.com/

Does the Router support virtual private networks (VPNs)?

The Router supports VPN passthrough, which allows VPN clients on
the LAN to communicate with VPN hosts on the Internet. It is also
possible to set up VPN hosts on your LAN that clients elsewhere on
the Internet can connect to, but this is not a recommended
configuration.

A

IP ADDRESSING

The Internet Protocol Suite

Managing the Router over the Network

IP Addresses and

Subnet Masks

The Internet Protocol suite consists of a well-defined set of
communications protocols and several standard application protocols.
Transmission Control Protocol/Internet Protocol (TCP/IP) is probably the
most widely known and is a combination of two of the protocols (IP and
TCP) working together. TCP/IP is an internationally adopted and
supported networking standard that provides connectivity between
equipment from many vendors over a wide variety of networking
technologies.

To manage a device over the network, the Router must be correctly
configured with the following IP information:

■ An IP address

■ A Subnet Mask

Each device on your network must have a unique IP address to operate
correctly. An IP address identifies the address of the device to which data
is being sent and the address of the destination network. IP addresses
have the format n.n.n.x where n is a decimal number between 0 and 255
and x is a number between 1 and 254 inclusive.

However, an IP address alone is not enough to make your device operate.
In addition to the IP address, you need to set a subnet mask. All networks
are divided into smaller sub-networks and a subnet mask is a number
that enables a device to identify the sub-network to which it is
connected.

96 APPENDIX A: IP ADDRESSING

For your network to work correctly, all devices on the network must have:

■ The same sub-network address.

■ The same subnet mask.

The only value that will be different is the specific host device number.
This value must always be unique.

An example IP address is ‘192.168.100.8’. However, the size of the
network determines the structure of this IP address. In using the Router,
you will probably only encounter two types of IP address and subnet
mask structures.

Typ e O n e

In a small network, the IP address of ‘192.168.100.8’ is split into two
parts:

■ Part one (‘192.168.100’) identifies the network on which the device

■ Part two (‘.8’) identifies the device within the network.

resides.

This type of IP address operates on a subnet mask of ‘255.255.255.0’.

See Ta bl e 4

for an example about how a network with three computers

and a Router might be configured.

Tab le 4 IP Addressing and Subnet Masking

Device IP Address Subnet Mask

PC 1 192.168.100.8 255.255.255.0

PC 2 192.168.100.33 255.255.255.0

PC 3 192.168.100.188 255.255.255.0

Router 192.168.100.72 255.255.255.0

Typ e Tw o

In larger networks, where there are more devices, the IP address of
‘192.168.100.8’ is, again, split into two parts but is structured differently:

■ Part one (‘192.168’) identifies the network on which the device

resides.

■ Part two (‘.100.8’) identifies the device within the network.

How does a Device Obtain an IP Address and Subnet Mask? 97

This type of IP Address operates on a subnet mask of ‘255.255.0.0’.

See Ta bl e 5

for an example about how a network (only four computers

represented) and a Router might be configured.

Tab le 5 IP Addressing and Subnet Masking

Device IP Address Subnet Mask

PC 1 192.168.100.8 255.255.0.0

PC 2 192.168.201.30 255.255.0.0

PC 3 192.168.113.155 255.255.0.0

PC 4 192.168.002.230 255.255.0.0

Router 192.168.002.72 255.255.0.0

How does a Device Obtain an IP Address and Subnet Mask?

There are three different ways to obtain an IP address and the subnet
mask. These are:

■ Dynamic Host Configuration Protocol (DHCP) Addressing

■ Static Addressing

■ Automatic Addressing (Auto-IP Addressing)

DHCP Addressing The Router contains a DHCP server, which allows computers on your

network to obtain an IP address and subnet mask automatically. DHCP
assigns a temporary IP address and subnet mask which gets reallocated
once you disconnect from the network.

DHCP will work on any client Operating System such as Windows

95,
Windows 98, Windows NT 4.0, Windows 2000 and Windows XP.
Also, using DHCP means that the same IP address and subnet mask will
never be duplicated for devices on the network. DHCP is particularly
useful for networks with large numbers of users on them.

Static Addressing You must enter an IP Address and the subnet mask manually on every

device. Using a static IP and subnet mask means the address is
permanently fixed.

Auto-IP Addressing Network devices use automatic IP addressing if they are configured to

acquire an address using DHCP but are unable to contact a DHCP server.
Automatic IP addressing is a scheme where devices allocate themselves

98 APPENDIX A: IP ADDRESSING

an IP address at random from the industry standard subnet of

169.254.x.x (with a subnet mask of 255.255.0.0). If two devices allocate
themselves the same address, the conflict is detected and one of the
devices allocates itself a new address.

Automatic IP addressing support was introduced by Microsoft in the
Windows 98 operating system and is also supported in Windows 2000
and Windows XP.