CCNA Exam Preparation / IP services
CCNA technique 152: DNS versus reachability — practice and verify
An original CCNA exercise on dns versus reachability with predictions, evidence, and a changed-condition check.
Environment and inputs: CCNA 200-301 v1.1 study; isolated Cisco IOS / IOS XE lab or paper exercise where applicable.
Practice task
Test a known lab server by address, then query its configured DNS record, and compare results.
Expected reasoning
Reaching an IP address while name lookup fails suggests a different path than a total forwarding outage.
Produce evidence
Use an isolated simulator, approved lab or paper trace. Record the topology, prediction and observed result. Before device changes, capture the relevant interface, route, neighbor or service state. Ping alone may not prove the behavior under study.
Introduce a counterexample
Change one condition in the dns versus reachability exercise and predict the result before checking it. Explain which observation would disprove your hypothesis. Restore the baseline, repeat from blank notes and keep both results.
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.