Trouble Shooting

• It’s Broken!

The BEST approach

Troubleshooting Tips

• Did the user back anything up?– No: Oh Well…– Yes: Proceed with troubleshooting

• Isolating the problem– If it ain’t broke don’t fix it!– Communicate with the user– Is it hardware failure or improper use?– Is the problem local or regional?

TROUBLESHOOTING FLOWCHART

************ * START * ************ || \/ ******************** YES * DOES * NO =======* THE DAMN THING *==== || * WORK ? * || \/ ******************** \/*********** ************ DON'T * * DID YOU * NO* FOOL * * FOOL * =====* WITH IT! * * WITH IT ? * ||*********** *********** || || || || || YES || || || || || || V || || ********** *********** || || ******** NO * DOES * * YOU * || || * HIDE <<==== ANYONE <<==== DUMBY! * || || * IT * * KNOW? * ********** || || ******** ********** || || || || V || || YES || **************** || || || YES * WILL YOU * || || ||<<========== * CATCH HELL? * || || || **************** || || \/ || || || ************ || NO || || * YOU POOR * || || || * DOPE * || || || ************ || || || || || || || || \/ || \/ V ******** ********* ==================>>* STOP <<==== TRASHCAN IT!* ******** *********

Troubleshooting

• Start With a PLAN!• Get the right amount of information

– Communicate with the user– not too much info– not enough info– Ask a lot of questions

• Analyze– Familiarize yourself with the system’s software and

hardware

Troubleshooting

• Prioritize– Network

• Local (fix it!)

• Wide Area (call someone to fix it!)

– Server– User

• Collect the data

• Isolate the problem

Ridge Hall computer assistant; may I help you?""Yes, well, I'm having trouble with WordPerfect.""What sort of trouble?""Well, I was just typing along, and, all of a sudden the words went away.""Went away?""They disappeared""Hmm. So what does your screen look like now?""Nothing""Nothing?""It's blank; it won't accept anything when I type."Are you still in WordPerfect, or did you get out?""How do I tell?""Can you see the C:\ prompt on the screen?""What's a sea-prompt?""Never mind. Can you move the cursor around on the screen?""There isn't any cursor. I told you, it won't accept anything when I type.""Does your monitor have a power indicator?""What's a monitor?""It's the thing with the screen on it that looks like a TV. Does it have a little light that tells you when it's on?""I don't know.""Well, Then look on the back of the monitor and find where the power cord goes into it. Can you see that?"......"Yes, I think so.""Great! Follow the cord to the plug, and tell me if it's plugged into the wall."......"Yes, it is.""When you were behind the monitor, did you notice that there were two cables plugged into the back of it, not just one?""No""Well, there are. I need you to look back there again and find the other cable."......"Okay, here it is.""Follow it for me, and tell me if it's plugged securely into the back of your computer.""I can't reach.""Uh huh. Well, can you see if it is?""No.""Even if you maybe put your knee on something and lean way over?""Oh, it's not because I don't have the right angle - it's because it's dark.""Dark?""Yes, the office light is off and the only light I have is coming in from the window.""Will, turn on the office light, then.""I can't""No? Why not?""Because there's a power outage.""A power... A power outage? Aha! Okay, we've got it licked now. Do you still have the boxes and manuals and packing stuff yourcomputer came in?""Well, yes, I keep them in the closet.""Good! Go get them, and unplug your system and pack it up just like it was when you got it. Then take it back to the store you bought itfrom.""Really? Is it that bad?""Yes, I'm afraid it is.""Well, all right then, I suppose. What do I tell them?""Tell them you're too stupid to own a computer."

More Jokes

A helicopter was flying around above Seattle when an electrical malfunction disabled all of the aircraft's electronic navigation and communications equipment. Due to the clouds and haze, the pilot could not determine the helicopter's position and course to steer to the airport. The pilot saw a tall building, flew toward it, circled, drew a handwritten sign, and held it in the helicopter's window.

The pilot's sign said "WHERE AM I?" in large letters. People in the tall building quickly responded to the aircraft, drew a large sign, and held it in a building window. Their sign said "YOU ARE IN A HELICOPTER." The pilot smiled, waved, looked at his map, determinedthe course to steer to SEATAC airport, and landed safely. After they were on the ground, the copilot asked the pilot how the "YOU ARE IN A HELICOPTER" sign helped determine their position. The pilot responded "I knew that had to be the MICROSOFT building because they gave me a technically correct, but completely useless answer."

Troubleshooting (cont)

• Tools– Software (programs, sniffers)– Hardware (line analyzers) Techniques– Systematic search– Top down (start at keyboard, end at internet)– Use Deja Vu (I’ve seen this before)

• Wheel Spinning

• Jumping to Conclusions

Tools

• Cable Tester– Continuity, length

• Wireless enabled laptop• Flashlight (Fiber)• Volt Meter (Digital or Analog)

– Voltages– Resistances

• TDR– Length and quality of cable.

More Tools

• Laptop booted with an unimpeachable operating system

• Knoppix (linux on CD)

• Since the OS is on CD, it can’t be corrupted (unless the CD image has a bug).

More Troubleshooting

• Look for the obvious

• Know when to ask for help

• Know who to ask for help

• Know what help to ask for

• Give details of the problem

• Try not to argue

Programs

• Traceroute

• Ping

• Winipcfg

• Ipconfig

• Netstat

• Nbtstat

• Telnet

Network Analysis

• Protocol Analyzers (Sniffer, Ethereal)– Bottlenecks– Broadcast storms– Unusual Patterns– Trends of traffic

• Use Network Graphing Tools– http://pomoxis.usu.edu

Hacker Monitors

• http://hut.ss.usu.edu– Tracks portscans, attacks, DOS

• http://disabled.usu.edu – Which systems N&CS has disabled.

Twisted Pair

• Proper category cable (cat 3 vs. cat 5)

• Proper crimping of connections

• Pinched or cut cables

• Link light abnormalities

• Is there an address conflict? (IP)

Twisted Pair Testing

• Continuity– Volt/Ohm meter

– 10baseT/100baseT hub/adapter will act as a short

• Time Domain Reflectometry– Simple network tester

• NEXT (Near End Cross Talk)– Complex (Expensive) network tester

– B.E.R.T. (Bit Error Rate Tester)

Time Domain Reflectometry

• Utilizes the speed of light 300,000,000 meters per second slowed by the medium being measured (velocity factor)

• Detector senses a reflection of the signal

• Timer measures the delay from incident wave (transmitted pulse) and reflected wave (received pulse)

Time Domain Reflectometry

Signal

(DB

)

Time (Microseconds)

Input Pulse Splice

End of cable (or break)

Fiber Installation

• Can be expensive but does solves some distance problems

• Installation required specialized equipment• Fibers are fragile• Fiber is not susceptible to electrical

disturbances• Fiber is secure (not easy to tap)• Somewhat easy to test

More Fiber Installation

• Single mode goes longer distances than multi mode but media is more expensive

• Needs careful optical alignment

• Individual fibers are fragile

• Each splice/connector increases line loss

• Transmit and receive on separate fibers

I hope it’s fixed!!!

The End

Remember Homework 5 on the web site