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Common ConnectivityProblems

Lesson Eight

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Exam Objectives

• Identify and troubleshoot name-resolution problems

• Identify and troubleshoot network adapter configuration problems

• Identify and troubleshoot LAN, Routing, and Remote Access configuration problems

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Lessons in this Chapter:

• Resolving Physical Connectivity Issues

• Resolving Network Configuration Issues

• Resolving Complex Networking Issues

• Resolving Name-Resolution Issues• Troubleshooting Internet

Connection Sharing

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Resolving Physical Connectivity Issues

• Malfunctioning cables, • Network interface cards (NICs),• Modems, • Hubs, or wireless access

points, or • Incorrect configuration of these

devices.

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Checking Connections

• The Ethernet cable to the hub• The Ethernet cables from the hub to

other computers• The physical connections to and

from routers and firewalls• The phone line to the phone jack• The modem, hub, and other devices

that need power to the wall jack• The universal serial bus (USB) or

FireWire cable

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Troubleshooting Installed Hardware

• Using Device Manager

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Troubleshooter

• Using Device Manager

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Basic Process

• Checking Physical Connections

• Using the Modem Troubleshooter

• Is the issue Global or Local

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Resolving Network Configuration Issues

• Modem connections.• Cable and DSL connections.• Workgroup connections.• Domain connections.

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Troubleshooting Modem Connections

• Physical problems• Configuration problems• User error

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Internet Properties

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Resolving Common Internet Connectivity Calls

• Table 8-1– Page 8-12

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Troubleshooting Cable and DSL Connections

• Connectivity problems include:– My dial-up modem keeps trying to

dial out.– My Internet connection is

unavailable.– I try to connect, but nothing

happens at all.– My Internet connection is slow.– I think I am getting interference.

Could something be causing that?

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Resolving Common Internet Connectivity Calls

• Table 8-2– Page 8-13

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Troubleshooting Workgroup Connections

• A few computers, each of which is connected to a hub, router, or switch through an Ethernet cable or wirelessly, for the purpose of sharing files in a small office or a home.

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Verify Logon Authentication

• Computer name

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Command Line Utilities

• IPCONFIG• NET CONFIG

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TCP/IP Properties

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Re-Creating the Network Connection

• Steps on page 8-18

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Troubleshooting Domain Connections

• Note – A computer running Windows XP

Home Edition cannot join a domain.

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Note

• Before performing any of the following troubleshooting techniques,– verify that physical connections are solid, – that the NIC has a green light indicating

that it is functional (if the NIC has diagnostic LEDs), and

– that switches, routers, and other devices are working properly and are available.

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Resolving Tier-1 Domain Connectivity Calls

• Page 8-20• Caution

– If the computer is not configured with the correct DNS server addresses (or cannot contact the DNS servers), you will not be able to change the computer’s membership.

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Network Diagnostics

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Network Connections

• DHCP• Static• APIPA

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Exam Tip

• On the exam, you will often be shown IP addressing information for use in troubleshooting a networking problem.

• Remember the range of IP addresses used by APIPA.

• If you see that a computer has an IP address starting with 169.254, it is a dead giveaway that a DHCP server is not being reached.

• This could happen because of a networking problem or a DHCP issue.

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Practice:

• Resolve Network Configuration Issues– Page 8-26

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Resolving Complex Networking Issues

• OSI Model• TCP/IP Tools work at the Network

layer– Ping

• Loopback• Local Address• Default Gateway• Remote Address

– IPCONFIG– Rules About TCP/IP Addressing

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IP Address Classes

Address Class

RangeDefault Subnet Mask

Networks/Nodes

Class A1.0.0.0 to 127.255.255.255

255.0.0.0126 networks of up to 16,777,214 nodes each

Class B128.0.0.0 to 191.255.255.255

255.255.0.016,382 networks of up to 65,534 nodes each

Class C192.0.0.0 to 223.255.255.255

255.255.255.02,097,150 networks of up to 254 nodes each

Class D224.0.0.0 to 239.255.255.255

NoneAll members of the multicast session share the same IP address

Class E240.0.0.0 to 255.255.255.255

NoneStrictly for research and experimentation purposes

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Using Net View

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If the Net View command fails

• Check the following:– The computer name in the

System Properties dialog box.– The gateway or router address in

the TCP/IP Properties dialog box.

– The gateway or router’s status.– The remote computer is running

the File and Printer Sharing for Microsoft Networks Service.

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More Tools

• Tracert• Pathping• Third party tools

– Internet web sites– NeoTrace

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Practice:

• Use Network Troubleshooting Tools– Page 8-36

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Resolving Name-Resolution Issues

• DNS– Internet Queries rely on DNS– HOST file is used for DNS

• WINS– NetBIOS Queries and browsing

rely on WINS– LMHOST.SAM file is used for

WINS

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HOST File

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LMHOST File

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Troubleshooting Internet Connection Sharing

• Configure Internet Connection Sharing.

• Identify the limitations of ICS.• Enable ICS

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Configuring Internet Connection Sharing

• ICS Limitations– Must have Two NICs– On XP only supports 10 user

connections– Limited to 192.168.0.0 network– Does not have IP address conflict

detection– ICS must be enabled from the dial-up,

virtual private network (VPN), broadband, or other connection to the Internet.

– Should not be used with DHCP, DNS, or Gateways

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Summary

• Case Scenario– Page 8-48

• Troubleshooting Lab– Page 8-49

• Exam Highlights– Page 8-50