5.7. Reflection Checkpoint
Key Takeaways
Before proceeding, ensure you can:
- Recite the eight-step troubleshooting methodology in order and explain what each step accomplishes — including why root cause analysis (7) is separate from documentation (8)
- Match hardware failure symptoms to their probable root causes: memory errors → random crashes and BSOD; CMOS battery → date/time reset; PSU failure → random shutdown under load
- Identify the correct network diagnostic command for each diagnostic question: IP config (ipconfig/ip addr), DNS (nslookup/dig), routing (tracert/traceroute), port testing (telnet/nc)
- Distinguish APIPA (DHCP failure) from physical link failure using link light state as the key differentiator
- Explain why "one change at a time" is a mandatory rule and not just a best practice
- Identify clock skew as a root cause of Kerberos authentication failures
- Recognize that SELinux denials can cause permission errors even when standard UNIX permissions appear correct
- Explain why RAID rebuilding creates a data loss window and what actions minimize risk during rebuild
Connecting Forward
Phase 6 is your exam-day toolkit: strategy for approaching questions, a quick-reference of the most critical facts, and practice questions spanning all four domains. Everything you've built in Phases 1–5 gets synthesized here into the actionable knowledge you'll apply in 90 minutes on exam day.
Self-Check Questions
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A server running Windows Server is unable to authenticate users against Active Directory. The server can ping the domain controller by IP address. Users get "The system cannot contact a domain controller to service the authentication request." List the three most likely causes in order of probability, and specify the diagnostic command for each.
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During a RAID 5 array rebuild, what is the maximum number of additional drive failures you can survive without data loss, and how does this differ from a RAID 6 array in the same scenario?
