CAS-004 Security Architecture Practice Question
A security administrator needs to ensure that only authorized devices can access the corporate network. Which technology would best enforce this requirement at the network access layer?
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
✓
802.1X
802.1X provides port-based authentication, allowing only authorized devices to connect to the network.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
TLS 1.3
Why it's wrong here
Incorrect; TLS secures communications, not network access.
- ✗
IPsec VPN
Why it's wrong here
Incorrect; VPN secures remote connections, not device authentication.
- ✓
802.1X
Why this is correct
Correct; 802.1X authenticates devices before granting network access.
- ✗
DNSSEC
Why it's wrong here
Incorrect; DNSSEC secures DNS.
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.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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