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Network Troubleshooting. Lesson 12. Objectives. Objectives. Objectives. Objectives. Objectives. One Size Does Not Fit All. Computers and networks are different Knowing how to fix one computer or one network does not necessarily mean you know how to fix them all
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Network Troubleshooting Lesson 12
One Size Does Not Fit All • Computers and networks are different • Knowing how to fix one computer or one network does not necessarily mean you know how to fix them all • Troubleshooting requires: • Knowledge • Intuition • Experience
Bringing the Steps of the Troubleshooting Process Together • Discussion: How would you go about bringing the steps of the troubleshooting process together? • An end user suddenly loses connectivity to the corporate network. She reports the problem to tech support. Tech support assigns you to resolve the issue.
Network Tools and What They Are Used For • Command-line interface (CLI) network tools • Hardware tools
Ipconfig • A command-line tool found in all current versions of Microsoft Windows • Displays the IP address, subnet mask, and default gateway of each adapter on which the computer is run
Ifconfig • Ifconfig = Interface Configuration • Linux/UNIX equivalent to ipconfig • Without parameters, ifconfig returns same information as ipconfig • However, ifconfig has many more parameters than ipconfig
Ping • Determines if a specific IP address is reachable on the network
Traceroute and Tracert • Traceroute • Linux/UNIX CLI tool that reports each stop a packet makes on way to a destination • IP address identifies the destination for which you wish to find the route to • Tracert • DOS/Windows equivalent to traceroute • Works the same as traceroute, uses fewer parameters
My Traceroute (MTR) • Linux/UNIX command-line tool that combines the capabilities and functionality of traceroute and ping
Pathping • Similar to the Linux mtr tool • Combines functionality of the ping and tracert commands
ARP Ping • A ping command using the ARP protocol to issue an “arp request” rather than the ICMP protocol to issue an “echo request” • Can only be performed in Linux/UNIX • Command to do an ARP ping is arping
ARP • Displays arp table of a computer • Arp table is kept by all network devices; contains the IP address and MAC address of all the other network devices with which it has been in contact
Nslookup • Looks up DNS servers; displays servers for a particular domain • Displays the IP address of the DNS server on the network being used to run nslookup
Hostname • Displays or changes the DNS hostname of the local machine • Output in UNIX/Linux and DOS/Windows environments is almost identical
Domain Information Groper (dig) • Queries DNS servers to gain information about them • Similar to nslookup, but dig can provide more detailed information • Only available in Linux/UNIX environments
Route • Used to view and/or manipulate the routing table located on the targeted device, either by adding or removing static routes • Sets up static routes to specific network locations from the local interface • Works the same way in both the Linux/UNIX and DOS/Windows environments
Nbtstat • Obtains information about a local machine and the devices it is connected to, based on NetBIOS names • Novell and Windows no longer use NetBIOS names for creating network IDs, so nbtstat is no longer in common usage
Netstat • Displays information about network connections, routing tables, interface statistics, masquerade connections, and multicast memberships • Works in both the Linux/UNIX and the DOS/Windows environment
Netstat (Linux/UNIX) Showing Active Protocols and Sockets on Local Computer
Netstat (DOS/Windows) Showing Open TCP Ports on Local Computer
Connectivity Software • Programs that connect computers or other types of electronic devices to another computer or a network • Is usually specifically designed for the device it is being used to connect and is hardware dependent • Usually comes with a test component
Hardware Tools • Tools that physically exist as opposed software programs • Several types of hardware tools are available for troubleshooting and fixing a network
Cable Tester • Tests the connectivity of various cables as well as any subcomponents within them • Can test allpairs in atwisted-pair wire
Cable Tester Designed to Test a Large Variety of Cable Wires
Protocol Analyzers • Software-based or hardware-based • Both capture and analyze network packets • Both test a network with a specific protocol • Hardware-based • Entirely self-contained system with software • Connect to a data jack • Tests if different network segments meet the specifications needed to run different types of data networks
Certifiers • Devices used to certifythat the cables in anetwork configurationmeet the requiredphysical specification
Time-Domain Reflectometers (TDRs) • Tests in-place cables • When connected to ametal cable, sends anelectrical pulse downthe wire • Response mayindicate a fault in thewiring and wherefault is located
Optical Time-Domain Reflectometer (OTDR) • Basically a TDR for fiber-optic cables • Works the same way as a TDR but designed for fiber-optic cable instead of copper cables
Multimeter • A device designed to take several types of measurements • Most multi-meters measurevoltage,amperage,resistance,and continuity
Throughput Testers • Devices or software programs that test how fast data is passes through a network connection • Hardware throughput testers used when network wiring is first run in a site where network wiring is being run • Software throughput testers are more often used after a network is in place
Toner Probe • A tool that finds the end of a long run of a specific cable • Works with atone generator
Butt Set • Also called “lineman phones” • Devices used in telephone communications • Technician connects the butt set to any phone connection and uses that connection like a regular phone, or tests the connection to make sure it is working • Butt sets often look like miniature phone handsets with alligator clips hanging off them