This CEH practice question tests your understanding of footprinting, reconnaissance and scanning. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A security analyst wants to gather information about a target domain without sending any packets to the target. Which technique should the analyst use?
Ping sweep
Why wrong: Ping sweep sends ICMP echo requests, which is active.
WHOIS lookup
WHOIS queries public databases without contacting the target directly.
Netcat banner grab
Why wrong: Netcat connects to a service to retrieve a banner, which is active.
Nmap SYN scan
Why wrong: Nmap sends packets to the target, making it active reconnaissance.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
WHOIS lookup
WHOIS lookup is a passive reconnaissance technique that queries public databases (e.g., RDAP or WHOIS servers) for domain registration details such as registrar, creation date, and administrative contacts. It requires no packets to be sent to the target domain's infrastructure, making it ideal for information gathering without direct interaction.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
Ping sweep
Why it's wrong here
Ping sweep sends ICMP echo requests, which is active.
WHOIS lookup
Why this is correct
WHOIS queries public databases without contacting the target directly.
Related concept
Read the scenario before looking for a memorised answer.
Netcat banner grab
Why it's wrong here
Netcat connects to a service to retrieve a banner, which is active.
Nmap SYN scan
Why it's wrong here
Nmap sends packets to the target, making it active reconnaissance.
Common exam traps
The trap here is that candidates confuse passive reconnaissance (no packets to the target) with active scanning techniques like ping sweeps or port scans, assuming any information gathering requires direct interaction.
Detailed technical explanation
WHOIS queries are typically made over TCP port 43 or via web-based RDAP endpoints, but the data is retrieved from authoritative registries (e.g., ARIN, RIPE) rather than the target itself. This technique falls under passive reconnaissance, which is crucial for avoiding detection by intrusion detection systems (IDS) or firewall logs that would flag active probes. In real-world engagements, WHOIS can reveal organizational structure, IP ranges, and even email addresses useful for social engineering.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A practitioner preparing for the CEH exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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FAQ
Footprinting, Reconnaissance and Scanning — This question tests Footprinting, Reconnaissance and Scanning — Read the scenario before looking for a memorised answer..
The correct answer is: WHOIS lookup — WHOIS lookup is a passive reconnaissance technique that queries public databases (e.g., RDAP or WHOIS servers) for domain registration details such as registrar, creation date, and administrative contacts. It requires no packets to be sent to the target domain's infrastructure, making it ideal for information gathering without direct interaction.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 24, 2026
This CEH 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 CEH exam.
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