If a network or a portion of a network goes down, it can have a severe negative impact on the business. Network administrators must use a systematic approach to troubleshooting when network problems occur to bring the network back to full production as quickly as possible.

The ability for a network administrator to be able to resolve network problems quickly and efficiently is one of the most sought after skills in IT. Enterprises need individuals with strong network troubleshooting skills and the only way to gain these skills is through hands-on experience and by using systematic troubleshooting approaches.

This chapter describes the network documentation that should be maintained and general troubleshooting procedures, methods, and tools. Typical symptoms and causes at several layers of the OSI model are also discussed. This chapter also includes some information about troubleshooting path and ACL issues.