Transcript TCP/IP Configuration (continued)

Chapter 13: Troubleshoot TCP/IP
MCDST 70-271: Supporting Users and Troubleshooting a
Microsoft Windows XP Operating System
Objectives
• Understand basic network configuration under
Windows XP
• Understand the basics of IP address
configuration
• Perform TCP/IP configuration
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Objectives (continued)
• Understand name resolution basics
• Use TCP/IP troubleshooting tools
• Resolve basic TCP/IP problems
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Network Connection Under
Windows XP
• A single, multifaceted interface that combines
networking access for LAN, Internet, and modem
• Accessed through Control Panel
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Network Connection Under
Windows XP (continued)
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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
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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)
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Modifying Existing Network Links
(continued)
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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
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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
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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
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IP Addressing (continued)
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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
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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
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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
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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
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TCP/IP Configuration (continued)
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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
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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
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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
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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
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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
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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
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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
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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
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TCP/IP Troubleshooting Tools
(continued)
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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
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PING Command Line Tool
(continued)
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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
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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
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Tracert Command Line Tool
(continued)
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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
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Nslookup Command Line Tool
(continued)
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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
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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
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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
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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
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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
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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
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