CCNA Exam Preparation / IP services
CCNA technique 151: DNS versus reachability — explain the decision
Explain dns versus reachability clearly, test your assumptions, and build a reusable CCNA recall routine.
Environment and inputs: CCNA 200-301 v1.1 study; isolated Cisco IOS / IOS XE lab or paper exercise where applicable.
Understand the distinction
Reaching an IP address while name lookup fails suggests a different path than a total forwarding outage.
Retrieve before reading
Close your notes and explain dns versus reachability in your own words. Draw the packet path, decision steps or study workflow. State when the explanation applies; a command or definition alone is not enough.
Apply it to a fresh example
Test a known lab server by address, then query its configured DNS record, and compare results.
Check your reasoning
Check your answer against the Cisco reference and lab evidence. Record the first incorrect assumption. Change one input, predict the new result and check it. Repeat later from blank notes.
Exam scope
Independent CCNA 200-301 v1.1 exercise, checked against Cisco resources on 2 November 2026. It is not a recalled exam question. The collection’s 200 techniques do not represent exam question counts or weights. Check Cisco’s current exam rules and your simulator’s supported syntax.