CCNA Network Services and Security Practice Question
Network Topology
You are connected to R1, a Cisco IOS-XE router acting as the network's DNS client. The network uses a local DNS server at 203.0.113.10 for internal name resolution. Users report that the hostname 'fileserver.courseiva.local' cannot be resolved, while other names work fine. Diagnose and fix the DNS resolution failure so that 'fileserver.courseiva.local' resolves correctly.
⚠ Common exam trap
Candidates often confuse client-side DNS configuration issues with server-side record problems. Remember: if some names resolve but others don't, the DNS server is reachable and functional; the missing record is the culprit. Do not change router settings unnecessarily.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Add an A record for 'fileserver' on the DNS server.
The DNS server is reachable (ping successful) and resolves other names (e.g., webserver.courseiva.local) correctly. However, 'fileserver.courseiva.local' returns NXDOMAIN, indicating the A record is missing from the DNS zone. Since the router is not the DNS server, the fix must be applied on the DNS server itself — not on R1. The candidate should understand that the problem is a missing DNS record, not a router configuration issue. The solution involves adding an A record for 'fileserver' (with the appropriate IP address) on the DNS server. On R1, verify connectivity to the DNS server and confirm that the domain lookup and name-server settings are correct, which they are. No router CLI changes are needed.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Add an A record for 'fileserver' on the DNS server.
Why this is correct
The NXDOMAIN response indicates that the DNS server has no record for 'fileserver.courseiva.local'. Adding the correct A record on the DNS server resolves the issue. The router's DNS client configuration is correct, as other names resolve.
- ✗
Configure the 'ip domain-lookup' command on R1 to enable DNS resolution.
Why it's wrong here
The 'ip domain-lookup' command is already enabled by default on Cisco IOS, and the router's successful resolution of other internal hostnames corroborates that DNS lookups are functioning correctly. This command only controls whether the router consults configured name servers for hostname-to-address resolution; it has no effect on the content of records held by the DNS server. Since the router is already sending queries and receiving NXDOMAIN responses, reissuing this command would change nothing.
- ✗
Change the DNS server address on R1 to 8.8.8.8.
Why it's wrong here
Pointing R1 to 8.8.8.8 (Google Public DNS) is counterproductive because that public server has no knowledge of the private 'courseiva.local' DNS zone and would return NXDOMAIN for every internal hostname. The existing DNS server at 203.0.113.10 is reachable and demonstrably resolves other internal names, which confirms the server address and network path are correct. The root cause is a missing A record on that local authoritative server, and changing the resolver address would break internal name resolution instead of fixing the missing record.
- ✗
Add a static host entry on R1 using 'ip host fileserver.courseiva.local 192.0.2.10'.
Why it's wrong here
This is incorrect because while a static entry would resolve the hostname locally, it does not fix the underlying DNS server issue. The problem is a missing DNS record, and a static entry is a workaround, not a proper fix.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 200-301 exam frequently reuses these exact scenarios with slightly different constraints.
✓Add an A record for 'fileserver' on the DNS server.Correct answer▾
Why this is correct
The NXDOMAIN response indicates that the DNS server has no record for 'fileserver.courseiva.local'. Adding the correct A record on the DNS server resolves the issue. The router's DNS client configuration is correct, as other names resolve.
✗Configure the 'ip domain-lookup' command on R1 to enable DNS resolution.Wrong answer — click to see why▾
Why this is wrong here
The specific factual error is that 'ip domain-lookup' is a global command that enables DNS resolution; if it were disabled, no names would resolve.
Why candidates choose this
Candidates may think the router's DNS client is misconfigured, but the symptom of partial resolution points to a server-side issue.
✗Change the DNS server address on R1 to 8.8.8.8.Wrong answer — click to see why▾
Why this is wrong here
The specific factual error is that the DNS server is functioning for other records; the problem is specific to one hostname, not the server address.
Why candidates choose this
Candidates might assume the DNS server is faulty and try a public DNS server, but that would not resolve internal names and is unnecessary.
✗Add a static host entry on R1 using 'ip host fileserver.courseiva.local 192.0.2.10'.Wrong answer — click to see why▾
Why this is wrong here
The specific factual error is that static entries bypass DNS but do not address the root cause; the DNS server should have the record for all clients.
Why candidates choose this
Candidates may see this as a quick fix on the router, but the question asks to 'diagnose and fix' the DNS resolution failure, implying a proper solution on the DNS server.
Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Visual reference
Quick reference
Common DNS Record Types
| Record | Purpose | Example |
|---|---|---|
| A | IPv4 address mapping | example.com → 93.184.216.34 |
| AAAA | IPv6 address mapping | example.com → 2606:2800::1 |
| CNAME | Alias to another hostname | www → example.com |
| MX | Mail server for domain | example.com → mail.example.com (priority 10) |
| TXT | Text data (SPF, DKIM, verification) | v=spf1 include:_spf.example.com ~all |
| NS | Authoritative name servers | example.com NS ns1.example.com |
| PTR | Reverse DNS (IP → hostname) | 34.216.184.93.in-addr.arpa → example.com |
| SOA | Zone authority record | Primary NS, admin email, serial, TTL defaults |
Go deeper
Related to this question
Learn chapter
Diagnosing DNS Record Issues — A, AAAA, CNAME, MX, NS, and PTR Records
Key term
A record
An A record is a type of DNS resource record that maps a domain name to an IPv4 address.
Key term
IP address
An IP address is a unique numerical label assigned to each device connected to a computer network that uses the Internet Protocol for communication.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 200-301 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 200-301 exam.