SSCP Network and Communications Security Practice Question
Which of the following is a connectionless transport layer protocol primarily used for services like DNS and DHCP?
⚠ Common exam trap
SSCP often tests the distinction between transport layer protocols (TCP/UDP) and network layer protocols (IP/ICMP), and candidates may incorrectly select IP or ICMP as transport layer protocols.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
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UDP
UDP (User Datagram Protocol) is a connectionless transport layer protocol that does not establish a session before sending data. It is used for services like DNS and DHCP because they require fast, lightweight communication without the overhead of TCP's three-way handshake. UDP operates at Layer 4 of the OSI model.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
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UDP
Why this is correct
UDP operates without establishing a session, sending datagrams independently with no handshake, acknowledgement, or retransmission. This connectionless design satisfies the stem's requirement, and its low overhead suits DNS and DHCP, which favour speed over guaranteed delivery. TCP, by contrast, is connection-oriented and would add unnecessary latency.
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IP
Why it's wrong here
IP is a connectionless network-layer protocol providing addressing and routing, not a transport-layer protocol, so it cannot serve DNS or DHCP transport needs. It is tempting because IP is connectionless and ubiquitous, but the question specifies transport layer, where UDP operates.
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TCP
Why it's wrong here
TCP is connection-oriented: it completes a three-way handshake and retransmits lost segments, so it cannot serve the connectionless DNS and DHCP exchanges the stem describes. It is tempting because TCP does carry DNS zone transfers and some DHCP-related traffic, but UDP is the transport those services actually use.
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ICMP
Why it's wrong here
ICMP is a connectionless network-layer protocol for error and diagnostic messages such as ping, carrying no ports or transport semantics for DNS and DHCP. It is tempting because it is connectionless and used by network services, but it is not a transport protocol.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official ISC2 exam blueprint
This SSCP practice question is part of Courseiva's free ISC2 certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the SSCP exam.