mediumMultiple Choice
DNS Host Record: Why Internal Websites Need a DNS Record
A small business reports that employees can access the internet but cannot reach the internal company website hosted on a local server. The server's IP address is 192.168.1.10, and clients use DHCP. What is the most likely cause?
Quick Answer
The answer is that the DNS server lacks a host record for the internal website. This is the most likely cause because when employees type the website’s hostname, their computers send a DNS query to resolve that name into an IP address; without a corresponding host record in the DNS zone, the query fails, and the browser cannot reach the server at 192.168.1.10. On the CompTIA A+ Core 1 220-1201 exam, this scenario tests your understanding of how internal DNS resolution differs from internet access—a common trap is assuming that internet connectivity guarantees local name resolution, but DHCP only provides IP configuration, not DNS records for private resources. Remember that a host record (an A record for IPv4) explicitly maps a hostname to a private IP, so if internal sites are unreachable by name but the internet works, always check the DNS server first. A helpful memory tip is “No A record, no arrival”—without that host record, the name simply cannot be found.
⚠ Common exam trap
CompTIA A+ exams often test the distinction between connectivity issues (like a down switch port or firewall block) and name resolution issues, trapping candidates who assume that internet access implies all DNS is working, when in fact internal DNS records may be missing or misconfigured.
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
✓
The DNS server lacks a host record for the internal website.
The internal website is accessed by its hostname, which clients resolve via DNS. Since employees can reach the internet (so general DNS works) but not the local server, the most likely cause is that the DNS server lacks a host record (A or AAAA record) for the internal website's name, preventing name-to-IP resolution for 192.168.1.10. DHCP is functioning correctly because clients receive IP addresses and can access the internet.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The DHCP server is not assigning the correct subnet mask.
Why it's wrong here
A wrong subnet mask from DHCP would typically break broader local communication, yet clients still reach the internet through the same DHCP scope, so addressing is functioning. It is tempting because DHCP misconfiguration is a common cause of partial connectivity, and it would fit if clients held addresses outside the server's subnet.
- ✓
The DNS server lacks a host record for the internal website.
Why this is correct
Internet access works because external names resolve through the DNS server, but the internal site fails because no host record maps its name to 192.168.1.10. Clients already hold valid DHCP leases and can reach the server by IP, isolating name resolution as the fault.
- ✗
The switch port connecting the server is administratively down.
Why it's wrong here
An administratively down switch port would cut all connectivity to the server, yet the stem says only the internal website is unreachable while internet access works. It is tempting because a downed port is a classic cause of total server unreachability, and it would be correct if clients could not reach the server at all.
- ✗
The firewall is blocking port 443 inbound.
Why it's wrong here
Blocking inbound port 443 would stop HTTPS to the internal site, but the stem gives no evidence the site uses TLS, and the server's plain HTTP access would remain unaffected. It is tempting because firewall rules commonly cause selective reachability, and it would be correct if only the HTTPS URL failed.
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 |
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Same concept, more angles
2 more ways this is tested on 220-1201
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A technician is troubleshooting a network where users can access the internet but cannot connect to a specific internal application server by its hostname. Pinging the server's IP address works. The DNS server is configured correctly for external names. What is the most likely cause?
medium- A.The DHCP server is out of IP addresses
- ✓ B.The DNS server does not have an A record for the application server
- C.NAT is misconfigured for the internal network
- D.The proxy server is blocking the hostname
Why B: Since users can access the internet and ping the server by IP, the network connectivity and external DNS resolution are working. The failure to resolve the internal server's hostname indicates that the DNS server lacks an A record for that specific hostname, preventing name-to-IP resolution for internal resources.
Variation 2. A company's internal website is accessible by IP address but not by its hostname. The website is hosted on a server with a static IP. Which service is most likely misconfigured?
medium- A.DHCP
- B.NAT
- ✓ C.DNS
- D.RADIUS
Why C: DNS resolves hostnames to IP addresses; if the site works by IP but not by hostname, name resolution is failing, which points to a DNS misconfiguration such as a missing or incorrect A record, wrong zone, or unreachable DNS server. The static IP working confirms the web server and network path are fine, isolating the fault to name resolution.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 220-1201 practice question is part of Courseiva's free CompTIA 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 220-1201 exam.