Network Troubleshooting Basics by Anthony Sequeira

Troubleshooting network issues is implicit in the responsibilities of a network administrator. Such issues could arise as a result of human error (for example, a misconfiguration), equipment failure, software bugs, or traffic patterns (for example high utilization or a network being under attack by malicious traffic).

The process of Troubleshooting, at its essence, is the process of responding to a problem report (sometimes in the form of a trouble ticket), diagnosing the underlying cause of the problem, and resolving the problem. Although you normally think of the troubleshooting process beginning when a user reports an issue, through effective network monitoring, you might detect a situation that could become a troubleshooting issue and resolve that situation before it impacts users.

After an issue is reported, the first step toward resolution is clearly defining the issue. After you have a clearly defined troubleshooting target, you can begin gathering information related to that issue. Based on the information collected, you might be able to better define the issue. Then you can hypothesize the likely causes of the issue. Evaluation of these likely causes leads to the identification of the suspected underlying root cause of an issue.

After a suspected underlying cause is identified, you define approaches to resolve an issue and select what you consider to be the best approach. Sometimes the best approach to resolving an issue cannot be implemented immediately. For example a piece of equipment might need to be replaced. However, implementing such an approach during working hours might disrupt a business's workflow. In such situations a troubleshooter might use a temporary fix until a permanent fix can be put in place.

Steps toDiagnose a Problem

Gather information. Because a typical problem lacks sufficient information to give a troubleshooter insight into a problem's underlying cause, the troubleshooter should collect additional information, perhaps using network maintenance tools or interviewing impacted users.
Duplicate the problem, if possible. Testing to see if you can duplicate the problem is often a key step in problem diagnosis.
Question Users. Although it can be difficult to gather information from your end users, doing so is often critical in correctly pinpointing the exact problem. Oftentimes, finding out user actions prior to the problem is critical.
Identify symptoms. What symptoms has the problem created.
Determine if anything has changed. Perhaps your end users will provide valuable clues if they accurately indicate what changes they might have made to systems.
Approach multiple problems individually. Unfortunately, you might discover that there are multiple issues. Be sure to approach each one individually.

About The Author

Anthony Sequeira, CCIE No. 15626, is a Cisco Certified Systems Instructor (CCSI) and author regarding all levels and tracks of Cisco Certification. Anthony formally began his career in the information technology industry in 1994 with IBM in Tampa, Florida. He quickly formed his own computer consultancy, Computer Solutions, and then discovered his true passion-teaching and writing about Microsoft and Cisco technologies. Anthony joined Mastering Computers in 1996 and lectured to massive audiences around the world about the latest in computer technologies. Mastering Computers became the revolutionary online training company, KnowledgeNet, and Anthony trained there for many years. Anthony is currently pursuing his second CCIE in the area of Security and is a full-time instructor for the next-generation of KnowledgeNet, Anthony is also a VMware Certified Professional.

CompTIA Network+ N10-008 Cert Guide contains proven study features that allow you to succeed on the exam the first time. Expert instructor Anthony Sequeira shares preparation hints and test-taking tips, helping you identify areas of weakness and improve both your conceptual knowledge and hands-on skills, essential for successful completion of the performance-based testing items on the exam. This complete, CompTIA-approved study package includes the following:

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An Exam Essentials appendix that quickly recaps all major chapter topics for easy reference, both in print and interactive digital format
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Network topologies and media types
IP addressing
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Data center architectures and cloud concepts
Routing, Ethernet switching, and wireless networking
Network availability and disaster recovery
Network security
Remote access
Network troubleshooting

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