Network Technician
DNS Failure Investigation
Practice separating DNS resolution problems from general IP connectivity problems.
Practice environment: This is an educational scenario. Work only on systems you own or are authorized to use. Follow employer, equipment and safety procedures in real environments.
STEP 1
Define the symptom
Record the hostname/application affected and whether other destinations work.
STEP 2
Check configuration
Confirm interface state, IP address, gateway and configured DNS resolver.
STEP 3
Test IP reachability
Use an approved known target to determine whether basic connectivity exists.
STEP 4
Test name resolution
Use a lookup tool to observe the DNS response and resolver being queried.
STEP 5
Compare evidence
Determine whether the problem appears local, resolver-related, record-related or outside your scope.
STEP 6
Document
Record commands/checks, outputs in summarized form, conclusion and escalation.
Finish the lab
Write a short ticket-style summary: symptom, scope, evidence, hypothesis, action or recommendation, and verification.