Drag and drop each protocol on the left to its matching characteristic on the right.
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Uses UDP transport; Combines authentication and authorization in one packet; Typically used for network access (e.g., 802.1X)
Encrypts entire packet payload; Separates authentication, authorization, and accounting into separate packets
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
RADIUS: Uses UDP transport
RADIUS uses UDP and encrypts only the password; TACACS+ uses TCP and encrypts the entire packet. RADIUS combines authentication and authorization; TACACS+ separates them. RADIUS is commonly used for network access; TACACS+ for device administration.
Quick reference
| 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.
Go deeper
Learn chapter
Network Architecture Fundamentals
Key term
802.1X Authentication
802.1X is a network access control protocol that prevents unauthorized devices from connecting to a wired or wireless network by requiring them to authenticate before gaining access.
Key term
RADIUS vs TACACS+
RADIUS and TACACS+ are two network protocols used to verify user identities and control access to network devices and services, with different approaches to security and flexibility.
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