- A
DHCP
Why wrong: DHCP assigns IP addresses, not authentication.
- B
DNS
Why wrong: DNS resolves names, not credentials.
- C
RADIUS
RADIUS authenticates users for network access, commonly used with 802.1X.
- D
NTP
Why wrong: NTP synchronizes time, not authentication.
Question 113 of 1,020
WPA2-Enterprise RADIUS Authentication
This 220-1201 practice question tests your understanding of network services. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A network administrator is deploying a new wireless network that requires users to authenticate using their domain credentials. The network uses WPA2-Enterprise. Which service must be configured to validate these credentials?
Quick Answer
The correct answer is RADIUS. WPA2-Enterprise relies on the 802.1X authentication framework, which requires a central authentication server to validate user credentials; RADIUS is the service that performs this role, typically checking domain credentials against Active Directory. On the CompTIA A+ Core 1 220-1201 exam, this concept tests your understanding of enterprise wireless security—specifically that WPA2-Enterprise uses 802.1X and RADIUS together, while WPA2-Personal uses a pre-shared key. A common trap is confusing RADIUS with DHCP or DNS, but remember that DHCP assigns IP addresses, DNS resolves names, and NTP syncs time—none handle authentication. To lock it in, use the mnemonic: “RADIUS Rules Authentication, DHCP Does IPs, DNS Does Names.”
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
✓
RADIUS
WPA2-Enterprise uses 802.1X authentication, which requires a RADIUS server to validate domain credentials against an authentication backend such as Active Directory. The RADIUS server acts as the Authentication Server (AS) in the 802.1X framework, receiving EAP packets from the access point and verifying the user's credentials before granting network access.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse RADIUS with DHCP or DNS because they associate 'domain credentials' with Active Directory, but they forget that RADIUS is the service that actually performs the authentication handshake in an 802.1X environment.
Detailed technical explanation
How to think about this question
In WPA2-Enterprise, the RADIUS server communicates with the authenticator (AP) using the RADIUS protocol (RFC 2865) and exchanges EAP frames encapsulated in RADIUS packets. A common real-world scenario is using Microsoft NPS (Network Policy Server) as the RADIUS server, which integrates with Active Directory to validate domain credentials and enforce network policies such as VLAN assignment or ACLs based on user or group membership.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A junior network technician can log in to a core router but cannot reach the enable prompt or configuration mode. The AAA server is authenticating the login — but the authorisation policy only grants privilege level 1, not 15. Authentication (who you are) is working; authorisation (what you can do) is not.
Quick reference
AAA Protocol Comparison
| Protocol | Port(s) | Encryption | Transport | Primary Use |
|---|---|---|---|---|
| RADIUS | 1812 / 1813 | Password only | UDP | Network access control |
| TACACS+ | 49 | Full packet | TCP | Device administration |
| Diameter | 3868 | Full session | TCP / SCTP | Carrier / mobile networks |
| 802.1X | — | EAP-based | Layer 2 | Port-based access control |
TACACS+ encrypts the entire packet; RADIUS only encrypts the password field — a key exam distinction.
What to study next
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FAQ
Questions learners often ask
What does this 220-1201 question test?
Network Services — This question tests Network Services — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: RADIUS — WPA2-Enterprise uses 802.1X authentication, which requires a RADIUS server to validate domain credentials against an authentication backend such as Active Directory. The RADIUS server acts as the Authentication Server (AS) in the 802.1X framework, receiving EAP packets from the access point and verifying the user's credentials before granting network access.
What should I do if I get this 220-1201 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Same concept, more angles
1 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 user complains that their laptop cannot connect to the company's wireless network, but other devices work fine. The network uses WPA2-Enterprise with 802.1X authentication. Which service is most likely misconfigured on the laptop?
medium- A.The DHCP server is out of addresses.
- B.The DNS server address is incorrect.
- C.The RADIUS server is offline.
- ✓ D.The 802.1X authentication method is set to PEAP instead of EAP-TLS.
Why D: Option D is correct because WPA2-Enterprise with 802.1X authentication requires the laptop to use a supplicant configured with the correct EAP method that matches the RADIUS server. If the laptop is set to PEAP (which uses a username/password or certificate) but the network requires EAP-TLS (which mandates client certificates), authentication will fail, preventing the laptop from connecting even though other devices with the correct configuration work fine.
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Last reviewed: Jul 4, 2026
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