Cisco Certified Network Associate (CCNA) Practice Exam

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Study for the Cisco Certified Network Associate (CCNA) exam with our comprehensive quiz featuring multiple-choice questions and detailed explanations. Prepare effectively and enhance your understanding of networking concepts!

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Which protocol matches TFTP traffic in an ACL?

TCP
UDP
ICMP
LDAP

The correct answer is: UDP

TFTP, or Trivial File Transfer Protocol, is designed to transfer files and operates over the User Datagram Protocol (UDP). Unlike TCP, which is connection-oriented and provides reliable data transmission, UDP is connectionless and does not guarantee delivery, making it suitable for simple file transfers where speed may be prioritized over reliability. When creating an Access Control List (ACL) to filter TFTP traffic, it's essential to match the protocol used by TFTP. Since TFTP utilizes UDP on port 69, any ACL rules intended to permit or deny TFTP traffic must specify UDP as the protocol to effectively match the packets being transmitted. This aligns with the fundamental concept of ACLs operating on layer 3 and layer 4 of the OSI model, where they examine both the IP address and the transport protocol. In contrast, TCP, ICMP, and LDAP are not applicable in this scenario since TFTP specifically does not operate over these protocols. Understanding the specific use of protocols in various network services, including TFTP, helps network professionals ensure proper configuration of ACLs to enhance network security and traffic management.