CPENT Iot And OT Exploitation Practice Question
A security analyst is performing a penetration test against a building automation system utilizing BACnet over IP. To discover BACnet devices on the local subnet without prior knowledge of their IP addresses, which specific network packet type and destination should the analyst send?
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
✓
A UDP broadcast packet containing a BACnet Who-Is request sent to port 47808
BACnet/IP uses a global broadcast UDP packet sent to port 47808 (0xBAC0) with a Who-Is service request to discover devices. Unicast TCP requests require prior IP knowledge, ICMP echo requests only show active hosts not BACnet services, and SNMP queries require a known community string.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
A UDP broadcast packet containing a BACnet Who-Is request sent to port 47808
Why this is correct
BACnet devices respond to a Who-Is broadcast message sent to UDP port 47808 by returning an I-Am message containing their device instance and IP address.
- ✗
An ICMP ping sweep to identify all live IP addresses on the local network segment
Why it's wrong here
An ICMP ping identifies live hosts but does not reveal specific BACnet application layer capabilities.
- ✗
An SNMP GETBULK request using the default private community string
Why it's wrong here
BACnet relies on its own application layer protocol rather than SNMP for device identification.
- ✗
A TCP SYN scan directed at port 47808 across the entire subnet
Why it's wrong here
BACnet/IP primarily operates over UDP, making a TCP SYN scan ineffective for discovering native BACnet services.
Visual reference
About these practice questions
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed August 2026 · checked against the official EC-Council exam blueprint
This CPENT practice question is part of Courseiva's free EC-Council 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 CPENT exam.