Guy's Best Practice & Litmus Tests Ezine #9 � Network Troubleshooting Tips
The theme of this week's ezine is advice for that moment when the system goes
down, and panic or frustration threatens to take over. As well as general
strategies, I also have a specific example to troubleshoot network connectivity
mysteries.
Contents for Ezine #9
Have you ever been on a roll where you solve problems easily? Remember that
feeling where nothing can stand in your way? Well hold that thought. If you have
ever read any Anthony Robbins, he is a great believer in getting into state. You
will be surprised what a difference a 'can do' attitude makes to problem
solving.
Here are the steps that I use in problem solving.
* Narrow the search. - Ask probing questions.
* Gather information. - Look for clues.
* Develop a theory - What is the most likely cause?
* Test your solution. - Try to alter only one setting at a time.
* Document what you are doing -Only the very best write down the changes they
make.
* Narrow the search - Ask questions.
Assuming that your initial flurry of activity failed to come up with an
answer, slow down and prepare a check list. Ideally, each question will halve the search area,
for example hardware or software. With 4 or 5 judicious questions, you
will soon narrow down the cause of the malfunction.
Calculating IP Address
ranges is a black art, which many network managers solve by creating custom
Excel spreadsheets. IPAT cracks this problem of allocating IP addresses
in networks in two ways:
For Mr Organized there is a nifty subnet
calculator, you enter the network address and the subnet mask, then IPAT
works out the usable addresses and their ranges.
For Mr Lazy IPAT
discovers and then displays the IP addresses of existing computers.
Download the Free IP Address Tracker
1) Does the problem stem from Hardware or Software?
2) Should we start with the client end or at the server?
3) Is it the Windows Operating System itself or is it an application like
Exchange or SQL?
4) What is the scope of the problem? One user or many workstations?
5) Which settings have changed? Have any programs been installed or uninstalled?
6) When did the problem start? Once you determine when it began, ask again -
what changed just before you noticed the problem?
Note: Never concern yourself with the question 'Who did it'. No-one ever owns
up! Your time is better spent looking for answers.
Let us take a common network failure and examine the techniques to solve the
problem. The situation is that you cannot print or copy files from the client XP
workstation to the Windows 2003 server.
Our first question is: Is this hardware or software. The second question should
be: What is the scope of the problem, one machine or several? Let us suppose
that in this example we have a software problem on one machine.
Now it's time to try ping, first the local gateway, then the server. Ping works,
but you still cannot connect to the server. (If it failed we could also try
TraceRT.) Next we try 'Net use' and Run, \\ server, neither command yields any
useful information. At his point we could ask the supplementary questions. What
has changed, and did it ever work!
Diagnosis: In situations where ping gives a response but you still cannot see
the server, strongly indicates a problem with DNS. It is worth running IPCONFIG
/all, but the place to change the configurations is at the TCP/IP properties
(Access though the Network Icon)
What to check: Default Gateway / DNS settings
What to change: If Manual IP -switch to Auto.
If auto IP (DHCP) - Try manual configuration.
Make sure that you add the IP address of at least one DNS server
When you are at the client and you change the IP address of the DNS
configuration, try IPCONFIG /registerdns; this saves a reboot. Check your
handiwork with IPCONFIG /all.
Connectivity tool kit
Ipconfig /all also /registerdns
Ping and PathPing
Tracert
NSLookup
On the server NETDIAG or DCDIAG
When a problem strikes, make the event logs one of the first places to check. Set the filter to
display just the red error messages. Be sure to sift through all 6 logs on a
domain controller: System, Application, Security, DNS, Active Directory, File
Replication Service.
Use the internet. These days I search Google ahead of searching TechNet. Ask a
question in a forum e.g. tek-tips.com. Just the act of formulating your question
will help to organize your thoughts, and could produce the answer. Registering
the question in the forum will open up the problem to thousands of techies; a
new friend in a different time zone may have seen your problem before and have
at least a partial answer.
While you are waiting for a reply from the forum, investigate Windows 2000 and
XP's built-in help. In particular try Help, Troubleshooters and check if you
have missed anything obvious.
Finally, once you have succeeded, if you write down how you solved the problem,
I guarantee that the problem will never reoccur. O.K, even if I am wrong, you
will have the answer ready! So make a folder for solved problems; save URL's of
handy sites such as tek-tips.com and add emails like this one?
See more interesting DNS, DHCP and IP articles
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33 DHCP • E 32 Tools •
Free CSV Import
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