CCNA Network Services and Security Practice Question
Network Topology
You are connected to R1 via the console. The network has a DNS server at 203.0.113.10 that should resolve www.example.com to 203.0.113.100. However, when you ping www.example.com, it fails. Diagnose and resolve the DNS resolution issue. The DNS server is reachable via ping, but nslookup from R1 returns a server failure. Configure R1 so that it can successfully resolve www.example.com. Additionally, verify that the DNS server is correctly configured for forward and reverse lookups.
⚠ Common exam trap
The exam trap is that candidates may confuse the 'ip name-server' command with 'ip host' or 'ip dns server'. They might also overlook the need to verify the DNS server's records. Always check the configured name-server IP first when DNS resolution fails.
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
✓
Configure 'ip name-server 203.0.113.10' under global configuration and ensure the DNS server has an A record for www.example.com pointing to 203.0.113.100.
The issue is that the DNS server IP address configured under 'ip name-server' is incorrect (10.0.0.2) instead of the actual DNS server (203.0.113.10). Additionally, the DNS server itself is not configured with the proper A record for www.example.com. The fix involves correcting the name-server address and ensuring the DNS server has the correct forward mapping. After correcting the name-server, nslookup and dig should return the IP address 203.0.113.100. For reverse lookup, a PTR record for 203.0.113.100 pointing to www.example.com must exist on the DNS server.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Configure 'ip name-server 203.0.113.10' under global configuration and ensure the DNS server has an A record for www.example.com pointing to 203.0.113.100.
Why this is correct
This is correct because the router's DNS resolver must be pointed to the correct DNS server IP. The 'ip name-server' command specifies the DNS server to use. Additionally, the DNS server must have the proper A record for the hostname to be resolved.
- ✗
Configure 'ip domain-lookup' and 'ip name-server 10.0.0.2' under global configuration, then verify with ping www.example.com.
Why it's wrong here
Configuring 'ip name-server 10.0.0.2' points the router's DNS resolver to an incorrect and likely unreachable address; the actual DNS server is 203.0.113.10. Even though 'ip domain-lookup' is enabled (it is actually on by default on most IOS images), all hostname resolution attempts will be sent to 10.0.0.2, which either does not exist or is not running DNS, so the query times out and the ping fails. To resolve www.example.com, the router must query 203.0.113.10 and that server must have the appropriate A record.
- ✗
Configure 'ip domain-lookup' and 'ip host www.example.com 203.0.113.100' under global configuration, then verify with ping www.example.com.
Why it's wrong here
This is incorrect because using a static host entry bypasses DNS resolution entirely. While it would make ping succeed, it does not resolve the DNS issue; the router would not query the DNS server, and nslookup would still fail.
- ✗
Configure 'ip dns server' under global configuration to make R1 act as a DNS server, then add an A record for www.example.com.
Why it's wrong here
This is incorrect because making R1 a DNS server is unnecessary and does not fix the issue. The problem is that R1 is not querying the correct DNS server; enabling DNS server functionality on R1 would require additional configuration and is not the intended solution.
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.
✓Configure 'ip name-server 203.0.113.10' under global configuration and ensure the DNS server has an A record for www.example.com pointing to 203.0.113.100.Correct answer▾
Why this is correct
This is correct because the router's DNS resolver must be pointed to the correct DNS server IP. The 'ip name-server' command specifies the DNS server to use. Additionally, the DNS server must have the proper A record for the hostname to be resolved.
✗Configure 'ip domain-lookup' and 'ip name-server 10.0.0.2' under global configuration, then verify with ping www.example.com.Wrong answer — click to see why▾
Why this is wrong here
The specific factual error: The name-server address must match the actual DNS server; using 10.0.0.2 will not resolve the hostname.
Why candidates choose this
Candidates might think that enabling domain-lookup is sufficient and that any DNS server will work, or they may confuse the IP addresses.
✗Configure 'ip domain-lookup' and 'ip host www.example.com 203.0.113.100' under global configuration, then verify with ping www.example.com.Wrong answer — click to see why▾
Why this is wrong here
The specific factual error: The 'ip host' command creates a static mapping, not a DNS resolution. The question requires DNS resolution to work, not a static override.
Why candidates choose this
Candidates might think that creating a static host entry is a valid fix for DNS problems, but it does not address the underlying DNS configuration.
✗Configure 'ip dns server' under global configuration to make R1 act as a DNS server, then add an A record for www.example.com.Wrong answer — click to see why▾
Why this is wrong here
The specific factual error: The 'ip dns server' command enables DNS server services on the router, but the router is not meant to be a DNS server in this scenario. The fix is to point to the existing DNS server.
Why candidates choose this
Candidates might confuse the client-side DNS resolver with the server-side DNS service, thinking that enabling DNS server on R1 will resolve the issue.
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
Name Server
A name server is a specialized server that translates human-readable domain names into machine-readable IP addresses so that computers can find each other on a network.
Key term
Fully Qualified Domain Name
A Fully Qualified Domain Name is the complete and unambiguous website or server name that includes the host, domain, and top-level domain, leaving no room for guesswork.
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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.