Which of the following is the default port for TACACS?

The correct answer is A. UDP port 49. TACACS (Terminal Access Controller Access-Control System) uses UDP port 49 as its default transport, distinguishing it from TACACS+ which uses TCP 49.

Network Traffic Analysis & Protocol Review

Question

Options

AUDP port 49
BTCP port 80
CTCP port 25
DTCP port 443

How the community answered

(27 responses)

A
85% (23)
B
7% (2)
C
4% (1)
D
4% (1)

Why each option

TACACS (Terminal Access Controller Access-Control System) uses UDP port 49 as its default transport, distinguishing it from TACACS+ which uses TCP 49.

AUDP port 49Correct

The original TACACS protocol operates over UDP port 49. This port assignment is defined by IANA and is the standard identifier used when referencing TACACS in network access control configurations. Knowing this port is essential for firewall rules and AAA server setup.

BTCP port 80

TCP port 80 is reserved for HTTP web traffic and has no association with TACACS.

CTCP port 25

TCP port 25 is the well-known port for SMTP email transmission, not authentication protocols.

DTCP port 443

TCP port 443 is reserved for HTTPS (HTTP over TLS/SSL) and is unrelated to TACACS.

Concept tested: TACACS default UDP port number

Source: https://www.cisco.com/c/en/us/support/docs/security-iam/terminal-access-controller-access-control-system-tacacs-/13838-10.html

Topics

#TACACS#authentication protocol#port numbers#AAA protocols

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