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220-1201 Practice Question: A technician is troubleshooting a network where…
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?
⚠ Common exam trap
CompTIA often tests the distinction between connectivity issues (IP reachable) and name resolution issues (hostname unreachable) to trap candidates into misdiagnosing DNS problems as routing or NAT failures.
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 does not have an A record for the application server
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.
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 out of IP addresses
Why it's wrong here
If users can access the internet, their devices have successfully obtained IP addresses, subnet masks, default gateways, and DNS server information from the DHCP server. DHCP exhaustion primarily impacts *new* devices attempting to join the network or existing devices whose leases have expired and cannot be renewed. Since the problem statement implies users *can* access the internet, their basic network connectivity and IP assignment are functional, making DHCP exhaustion an unlikely cause for an application server access issue.
- ✓
The DNS server does not have an A record for the application server
Why this is correct
An A (Address) record maps a hostname to an IPv4 address. If the DNS server lacks an A record for the application server's hostname, client devices will be unable to resolve the server's name to its corresponding IP address. While the application server might be fully operational and reachable directly by its IP address, applications and users typically rely on hostnames for access, leading to a "server not found" error when attempting to connect via name. This scenario perfectly aligns with users being able to access the internet (implying general DNS functionality) but failing to reach a specific internal application by name.
- ✗
NAT is misconfigured for the internal network
Why it's wrong here
Network Address Translation (NAT) is primarily used to translate private IP addresses of an internal network into public IP addresses when communicating with external networks, such as the internet. Since users can access the internet, NAT is likely functioning correctly for outbound external traffic. Internal network communication, like accessing an application server within the same local network, typically does not traverse a NAT device, making NAT misconfiguration irrelevant to this specific internal connectivity problem.
- ✗
The proxy server is blocking the hostname
Why it's wrong here
A proxy server acts as an intermediary for requests from clients seeking resources from other servers. While a proxy server *could* be configured to block access to specific hostnames, this scenario usually results in a "proxy denied" or "access forbidden" message. The problem implies a failure to *locate* the server by name, which is a fundamental name resolution issue. A missing DNS record is a more direct and foundational cause for a hostname not being resolvable, preceding any proxy-based blocking.
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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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.