Examkin

Question

Difficulty: MediumCommon Ports and Protocols

A network administrator is deploying a new centralized AAA server to manage administrative authentication for enterprise network switches. The deployment requires using TACACS+ to separate authentication, authorization, and accounting functions while encrypting the entire payload. However, authentication requests from the switches are currently being blocked by an intervening network firewall. Which port and transport layer protocol combination must be permitted on the firewall to allow TACACS+ traffic?

  1. TCP port 49Answer
  2. B
    UDP port 1812
  3. C
    UDP port 49
  4. D
    TCP port 389

Answer

TCP port 49 is required for TACACS+ communications.
TACACS+ operates over TCP port 49 by default. It utilizes TCP at the transport layer to provide reliable delivery and connection management while combining authentication, authorization, and accounting over a single port with full payload encryption.

Step-by-Step Solution

1
Identify the protocol specified in the requirement.
The scenario specifies TACACS+ (Terminal Access Controller Access-Control System Plus) for centralized network administrator AAA functionality.
Determining the target application protocol is the first step in matching port and transport requirements.
2
Determine the transport layer protocol used by TACACS+.
TACACS+ uses Transmission Control Protocol (TCP) because it requires connection-oriented reliability for AAA transactions.
Unlike RADIUS which relies on UDP, TACACS+ uses TCP at Layer 4.
3
Identify the default well-known port number for TACACS+.
The IANA standard port for TACACS+ is port 49.
Permitting TCP port 49 on the network firewall ensures TACACS+ traffic flows correctly between network switches and the AAA server.

Key Concept

Standard AAA protocols and default port mappings (TACACS+ vs RADIUS)
Estimated Time:1m 0s
Rate this question

Topics

Common Ports and Protocols

More questions from this topic