3COM 3CR858-91 User Manual

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6 TROUBLESHOOTING

Basic Connection

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

Checks

telephone line, and that all the equipment is powered on. Check that

 

the LAN Status LED and Cable/DSL Status LED on the Router are

 

illuminated, and that any corresponding LEDs on the NIC are also

 

illuminated.

 

Ensure that the computers have completed theirstart-upprocedure

 

and are ready for use. Some network interfaces may not be correctly

 

initialized until the start-upprocedure has completed.

 

If the LAN Status LED does not illuminate for a port that is connected,

 

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

Browsing to the Router Configuration Screens

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 NIC 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,Setting Up Your Computers. Restart your computer while it is connected to the Router to ensure that your computer receives an IP address.

When entering the address of the Router into your web browser, ensure that you use the full URL including the http:// prefix (for example, 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 onInternet Options. Select the

92 CHAPTER6: TROUBLESHOOTING

Connections tab and click on theLAN Settings button at the bottom.

Make sure that the Proxy Server option is unchecked.

If you cannot browse to the Router, use the winipcfg utility in Windows 95/98/ME to verify that your computer has received the correct address information from the Router.

From the Start menu, chooseRun and then enterwinipcfg. Check that the computer has an IP address of the form 192.168.1.xxx (where xxx is in the range2-254),the subnet mask is 255.255.255.0, and the default Router address is 192.168.1.1. If these are not correct, use theRelease andRenew functions to obtain a new IP address from the Router.

Under Windows 2000 and Windows XP, use the ipconfig command-lineutility to perform the same functions.

Connecting to the

If you can browse to the Router configuration screens but cannot access

Internet

sites on the Internet, check the following:

 

Confirm that the physical connection between the Router and the

 

cable/DSL modem is OK, and that the Cable/DSL Status LEDs on both

 

Router and modem are illuminated.

 

Confirm that the connection between the modem and the cable/DSL

 

interface is OK.

 

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. Refer to “Internet

 

Settings” on page 42.

 

For DSL users, check that the PPPoE or PPTP user name, password and

 

service name are correct, if these are required. Only enter a PPPoE

 

service name if your ISP requires one.

 

For cable users, check whether your ISP requires a fixed MAC

 

(Ethernet) address or Host Name. If so, use the Hostname and MAC

 

Address screen in Internet settings to ensure that the correct Host

 

Name or MAC address is presented. Refer to “Hostname & MAC” on

 

page 50.

 

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.

Forgotten Password and Reset to Factory Defaults

93

Forgotten Password If you can browse to the Router configuration screen but cannot log inand Reset to because you do not know or have forgotten the password, follow theFactory Defaults steps below to reset the Router to it’s factory default configuration.

CAUTION: All your configuration changes will be lost, and you will need to run the configuration wizard again before you canre-establishyour 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 the reset would be convenient.

1Remove power from the Router.

2Disconnect all your computers and the cable/DSL modem from the Router.

3Using a straight through Ethernet cable, connect the Ethernet Cable/DSL port on the rear of the Router to any one of the LAN ports.

4Re-applypower to the Router. The Alert LED will flash as the Router starts up, and after approximately 30 seconds will start to flash more slowly (typically 2 seconds on, 2 seconds off). Once the Alert LED has started to flash slowly, remove power from the Router.

5Remove the cable connecting the Cable/DSL port to the LAN port, and reconnect one of your computers to one of the Router LAN ports.

6Re-applypower to the Router, and when thestart-upsequence has completed, browse to:

http://192.168.1.1

and run the Setup Wizard. You may need to restart your computer before you attempt this.

7When the Setup Wizard has completed, you may reconnect your network as it was before.

Alert LED

The Alert LED will flash when the Router unit is first powered up while

 

the system software checks the hardware for proper operation. Once the

 

Router has started normal operation, the Alert LED will go out.

 

If the Alert LED does not go out following start up, but illuminates

 

continuously, this indicates that the software has detected a possible

 

fault with the hardware. Remove power from the Router, wait 10

 

seconds and then re-applypower. If the Alert LED comes on

 

continuously again, then a fault has been detected. Locate the copy of

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the Router software on the accompanying CD-ROMor 3Com web site (http://www.3com.com) and upload it to the Router to see if this clears the fault (refer to “Recovering from Corrupted Software” below). If this does not fix the problem, contact your supplier for further advice.

During normal operation, you may notice the Alert LED lighting briefly from time to time. This indicates that the Router has detected a hacker

 

attack from the Internet and has prevented it from harming your

 

network. You need take no specific action on this, unless you decide

 

that these attacks are happening frequently in which case you may

 

wish to discuss this with your ISP. The Router logs such attacks, and

 

this information is available through the Status and Logs screens.

 

 

Power LED or

Check that your Router is receiving power by looking at the status of

Power Adapter OK

the Power LED on the front panel and the Power Adapter OK LED on

LED Not Lit

the rear panel:

 

If both LEDs are lit green then the unit is receiving power.

 

If both LEDs are unlit then no power is being supplied to the unit.

 

Check that the power adapter is plugged into a working mains

 

outlet and that the mains outlet is supplying power. If the mains

 

socket is supplying power then the power adapter or power

 

adapter connection may be faulty. See “Replacement Power

 

Adapters” below.

 

If the Power Adapter OK LED is lit but the Power LED is unlit then

 

there may be a fault with your unit. Contact 3Com Technical

 

Support.

 

Check that you are using the correct power adapter for your Router.

 

You should only use the power adapter supplied with your Router.

Replacement Power If both the Power Adapter OK LED and Power LED are off, check yourAdapters power adapter connection. If the mains outlet is working and is capable

of supplying power to other devices, contact 3Com Technical Support and ask for a replacement power adapter. Please quote the power adapter part number shown on the OfficeConnect power adapter you are using.

Alternatively, quote the part number for your region:

Recovering from Corrupted Software

95

Table 3 Power Adapter Part Numbers

Part Number

Region

 

 

3C16760

US and Canada

3C16761

UK

3C16762

Europe and Middle East

3C16763

Australasia (except Japan and Korea)

3C16764

South Africa

3C16766

Japan

3C16767

Korea

3C16768

Argentina

 

 

Recovering from If the system software has become corrupted, the Router will enter aCorrupted Software “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.

Before you start, 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.

The latest software is available on 3Com’s Web site at:

www.3com.com

1Remove power from the Router and disconnect all your computers, except for the one computer with the software image.

2Reconfigure this computer to obtain an IP address automatically (see “Obtaining an IP Address Automatically” onpage 21)

3Restart the computer, and re-applypower to the Router.

4Using 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.

5Follow the on-screeninstructions. Enter the path and filename of the software image file.

6When the upload has completed, the Router will restart, run the self-testand, if successful, resume normal operation.

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

Frequently Asked

Questions

How do I reset the Router to Factory Defaults?

Either:

If you can log in, refer to “Reset to Factory Defaults” onpage 73. Or

If you have forgotten your password, and can not log on, see “Forgotten Password and Reset to Factory Defaults”onpage 93..

How many computers on the LAN does the Router support?

A maximum of 253 computers on the LAN are supported.

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 hubs 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 has a Virtual Private Network (VPN) feature that provides a secure link between remote users and the corporate network by establishing an authenticated and encrypted tunnel for passing secure data over the Internet. Refer to “VPN” onpage 64.

Where can I download software updates for the Router?

Updates to the Router software are posted on the 3Com support web site, accessible by visiting:

http://www.3com.com

Frequently Asked Questions

97

After you have downloaded the software from the 3Com Web site, you can upgrade your Router as described in “Upgrade” onpage 75.

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A

IP ADDRESSING

 

The Internet

The Internet protocol suite consists of a well-definedset of

Protocol Suite

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.

Managing the Router over the Network

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

An IP address

A Subnet Mask

IP Addresses and Each device on your network must have a unique IP address to operateSubnet Masks 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-networksand a subnet mask is a number that enables a device to identify thesub-networkto which it is connected.

100 APPENDIXA: IP ADDRESSING

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

The same sub-networkaddress.

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.

Type One

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 resides.

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

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

See Table 4 for an example about how a network with three computers and a Router might be configured.

Table 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

 

 

 

Type Two

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.