MCDST 70-271: Supporting Users and Troubleshooting a Microsoft Windows XP Operating System

MCDST 70-271: Supporting Users and Troubleshooting a Microsoft Windows XP Operating System

Chapter 13: Troubleshoot TCP/IP

Guide to MCDST 70-271 2

Objectives

• Understand basic network configuration under Windows XP

• Understand the basics of IP address configuration

• Perform TCP/IP configuration


Objectives (continued)

• Understand name resolution basics• Use TCP/IP troubleshooting tools• Resolve basic TCP/IP problems


Network Connection Under Windows XP

• A single, multifaceted interface that combines networking access for LAN, Internet, and modem

• Accessed through Control Panel


Network Connection Under Windows XP (continued)


Creating New Network Links

• Network Connections – Used to create and configure network connections

• Create a new connection command in the Network Tasks list – Starts a wizard that takes the user through the

process of establishing new network links


Modifying Existing Network Links

• Existing local area connections– Can be configured by opening the Properties

dialog box for a particular object• Components of connection objects

– Client: Client for Microsoft Networks– Service: QoS Packet Scheduler– Service: File and Printer Sharing for Microsoft

Networks– Protocol: Internet Protocol (TCP/IP)


Modifying Existing Network Links (continued)


Menu Options in Network Connections

• File: Disable– Prevents selected Connection object from being

used to establish a communications link• File: Enable

– Allows selected Connection object to be used to establish a communications link


Menu Options in Network Connections (continued)

• File: Connect– Initiates the selected Connection object to

establish a communications link• File: Status

– Displays a Status window for the selected Connection object


IP Addressing

• IP addresses– Logical addresses that are 32 bits (4 bytes) long

• Internet Protocol (IP) – Fast but unreliable

• Part of the IP address assigned to a computer – Designates which network the computer is on– Represents the host ID of that computer


IP Addressing (continued)


The Role of Classes

• Class A address– First octet is used to identify network and three

trailing octets are used to identify the hosts• Class B address

– First two octets identify the network and the second two identify the host

• Class C address – Use the first three octets for the network portion

and the final octet for the host


The Role of Classes (continued)

• Subnet mask– Used to determine which part of an address

denotes the network and which part the host• Subnet

– Can be written as 255.255.0.0– Can also be written as 172.16.1.1/16


Uniqueness of an IP Address

• Each IP address must be unique on the Internet• If two IP addresses are duplicated, neither

machine with that address is able to access the network

• To define an IP address, you must configure the TCP/IP protocol


TCP/IP Configuration

• Items that you might need to obtain from a network administrator– Unique IP address for computer– Subnet mask for the network to which the

computer belongs– Address of the default gateway– Address of one or more DNS servers, to provide

IP name resolution services– You might need to provide an address for a WINS

server


TCP/IP Configuration (continued)


TCP/IP Configuration (continued)

• Assign an IP address to a computer manually or through DHCP

• DHCP – Used to automatically configure the TCP/IP

settings for a computer• Default gateway for a computer

– Specifies host to which computer should send data that is not destined for the computer’s subnet


Name Resolution

• An essential service for – Moderate- to large-sized networks – Any system (or network) wishing to communicate

with the Internet• Forms of name resolution

– Domain name to IP address – Computer name to IP address


The HOSTS File

• A static file placed on members of a network to:– Provide a resolution mechanism between host

names and IP addresses– Used on small networks where the deployment of

a DNS server is unwarranted – Used on remote systems to reduce traffic over

slow WAN links– Can be used to hard-code important systems,

such as mission-critical servers


DNS

• Handles job of translating symbolic name, such as www.microsoft.com into a corresponding numeric IP address (207.46.250.252)

• Can provide reverse lookup services • Highly distributed database that organizes IP

names into hierarchical domains


LMHOSTS File

• Static file placed on members of a network to provide a resolution mechanism between NetBIOS names and IP addresses

• Used only on small networks where deployment of a WINS server is unwarranted

• Each line of an LMHOSTS file contains an IP address followed by the corresponding NetBIOS name


WINS

• Not a true native TCP/IP service• An extension added by Microsoft• Dynamic service used to replace the static

mechanism of the LMHOSTS file


Resolving Name Resolution Problems

• Only troubleshooting task a DST can perform to resolve problems with name resolution is verifying proper configuration of DNS and WINS server addresses– Check contents of the HOSTS or LMHOSTS files– Ping various systems to test for resolution

• Otherwise, name resolution problems must be forwarded to the network administrator


TCP/IP Troubleshooting Tools

• Ipconfig command line tool – Used to manage and view information related to

DHCP and DNS– When used without any parameters, displays the

IP address, subnet mask, and default gateway for all network interfaces on local machine


TCP/IP Troubleshooting Tools (continued)


PING Command Line Tool

• Uses the Internet Control Message Protocol (ICMP) protocol to inquire if a designated host is reachable on the network

• Used to request a response from a remote host• Provides information about round-trip time

required to deliver a message to machine and receive a reply


PING Command Line Tool (continued)


PING Command Line Tool (continued)

• Used to test network latency on each intermediary hop between a local source client and a destination

• Might be helpful as the tool to use after ping, if a failure is detected

• May be able to indicate last node, system, or hop that responded to echo requests before the communications failure occurred


Tracert Command Line Tool

• Used to determine the path employed by an ICMP echo request message

• Displays list of all encountered routers between client and target system along with time to live (TTL) field values


Tracert Command Line Tool (continued)


Nslookup Command Line Tool

• Used to translate an FQDN into an IP address using DNS

• Used to verify that a system’s full name is properly registered in DNS

• Proper syntax to test a system’s registration– nslookup FQDN


Nslookup Command Line Tool (continued)


ARP

• Used to associate a logical (IP) address to a physical (MAC) address

• Command is used to view and modify the contents of the ARP cache


The Use of the Repair Button

• Appears on the Support tab of a connection object’s Status dialog box

• Can be used to resolve basic problems with DHCP and name resolution caches

• Can be used as a troubleshooting technique


Troubleshooting TCP/IP Problems

• Use ipconfig from a Command Prompt to view the current TCP/IP configuration

• If IP address begins with 169, system did not receive an assigned IP address configuration from DHCP


Troubleshooting TCP/IP Problems (continued)

• If IP address is 0.0.0.0:– Network cable is disconnected– Device driver for the NIC is not loaded– IP address is a duplicate of another system on the

same segment• Verify that subnet mask is correct • Verify that the default gateway, DNS, and WINS

addresses are correct


Summary• Windows XP Professional provides network

access primarily by using TCP/IP• TCP/IP

– Routable– Supports enterprise-level networks– Has been designed to interconnect dissimilar

types of computers– An industry-standard protocol that provides easy

cross-platform communication– Thorough knowledge is important


Summary (continued)

• Windows XP – Includes a number of applications that utilize

TCP/IP and provide Internet connectivity– Can use a wide variety of name resolution

solutions– Includes several tools for viewing, altering, and

troubleshooting TCP/IP configuration

MCDST 70-271: Supporting Users and Troubleshooting a Microsoft Windows XP Operating System

Documents

network connectionsfile

network portion

network connectionscreate

ip addresseach ip address

new network linksguide

network tasks list

ip nam

ip addressing continuedguide