4.0 Troubleshooting

4.5 Given a scenario, troubleshoot wired and wireless networks with appropriate tools.

  • Common symptoms

    • No connectivity

    • APIPA address

    • Limited connectivity

    • Local connectivity

    • Intermittent connectivity

    • IP conflict

    • Slow transfer speeds

    • Low RF signal

  • Tools

    • Cable tester

      Cable Tester - Computer Hope

    • Loopback plug A loopback plug is a connector used for diagnosing transmission problems. It plugs into a port, such as a serial, parallel, or an Ethernet port and crosses the transmit line to the receive line so that outgoing signals can be redirected back into the computer for loopback testing.

    • Punch down tools

    • Toner probes

    • Wire strippers

    • Crimper

    • PING The PING utility tests connectivity between two hosts by sending an ICMP Echo Request to a destination host to verify IP connectivity. Ping can also be used to isolate network hardware problems and incompatible configurations by providing indicators of the general speed or reliability of network connections.

      Command options include:

      • -t : Pings the specified host until stopped
      • -a : Resolves addresses to hostnames
      • -n : Count Number of echo requests to send
      • -l : Adjusts the size of the ping packet
      • -w : Adjusts the time-out (in milliseconds)
      • hostname : Tests connectivity to a particular host

    • IPCONFIG The IPConfig command line utility is used to display or set TCP/IP configuration settings of network interfaces including the IP address, subnet mask, default gateway, MAC address, and DNS names. It also helps with reconfiguration of your IP address through release and renew.

      To use Ipconfig in Windows 2000 or XP;

      • Begin with Start, and select Run. This opens the "Run Line" dialog frame. Type cmd on the line and press Enter to invoke the Command Prompt utility. At the command prompt, type ipconfig, and press Enter.

      In Windows 7;

      • Begin with Start, type cmd in the Search Bar and press Enter to invoke the Command Prompt utility. At the command prompt, type ipconfig, and press Enter.

      Optional switches for Ipconfig include:

      • /? Displays the Help menu for ipconfig.
      • /all Displays full configuration information.
      • /release Releases the IP address for the specified adapter.
      • /renew Renews the IP address for the specified adapter.

    • TRACERT Traceroute is a utility program very similar to Ping, except that Tracert identifies the network path of test data sent to a remote computer, rather than the time it takes for each packet to return. It will list all the routers it passes through until it reaches its destination, or fails to and is discarded. In addition to this, it will tell you how long each 'hop' from router to router takes.

    • NETSTAT Netstat (Network Statistics) is a command-line tool that displays network connections (both incoming and outgoing), routing tables, and a number of network interface statistics. It is available on Unix, Unix-like, and Windows NT-based operating systems.

    • NBTSTAT Nbtstat (NetBios over TCP/IP) is designed to help troubleshoot NetBIOS name resolution problems. When a network is functioning normally, NetBIOS over TCP/IP resolves NetBIOS names to IP addresses.

    • NET

      The NET Command is used to manage network resources.

    • Wireless locator


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