CompTIA Security+ Question C-14

A company’s legacy server requires administration using Telnet. Which of the following protocols could be used to secure communication by offering encryption at a lower OSI layer? (Select TWO).

A. IPv6
B. SFTP
C. IPSec
D. SSH
E. IPv4

Answer: A,C

Explanation:
Telnet supports IPv6 connections. IPv6 is the communications protocol that provides an identification and location system for computers on networks and routes traffic across the Internet. IPsec is a protocol suite for securing Internet Protocol (IP) communications by authenticating and encrypting each IP packet of a communication session. IPsec is a compulsory component for IPv6.

IPsec operates at Layer 3 of the OSI model, whereas Telnet operates at Layer 7.