The answer is dnsrecon -d example.com -t axfr, as this command directly attempts a DNS zone transfer using the AXFR query type against the target’s authoritative nameservers. A zone transfer is designed to replicate DNS records between servers, so a successful AXFR request returns the entire zone file, including all subdomains, making it the most efficient method for DNS zone transfer enumeration during reconnaissance. On the Certified Ethical Hacker CEH exam, this question tests your understanding of DNS enumeration tools and the specific flags that trigger a zone transfer attempt; a common trap is confusing dnsrecon with nslookup or dig, which require manual server specification and lack the automated AXFR flag. Remember that the -t axfr flag is the key differentiator—think “AXFR = All X-Fer Records” to recall that it pulls every record in one shot.
CEH Footprinting, Reconnaissance and Scanning Practice Question
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 is performing reconnaissance on a target domain and wants to discover all subdomains using DNS enumeration. Which of the following commands would be MOST effective for performing a DNS zone transfer attempt?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
dnsrecon -d example.com -t axfr
Option D is correct because the `-t axfr` flag in `dnsrecon` specifically attempts a DNS zone transfer (AXFR query) against the target domain's authoritative nameservers. A successful zone transfer returns all DNS records, including all subdomains, making it the most direct and effective method for subdomain enumeration via DNS zone transfer.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
dig example.com ANY
Why it's wrong here
This queries all record types but does not perform a zone transfer. Zone transfer requires +transfer or -t AXFR.
✗
nslookup -type=ns example.com
Why it's wrong here
This queries NS records, not a zone transfer.
✗
theHarvester -d example.com -l 500 -b google
Why it's wrong here
theHarvester uses search engines to find subdomains, not DNS zone transfer.
✓
dnsrecon -d example.com -t axfr
Why this is correct
dnsrecon with -t axfr specifically attempts a zone transfer. However, dig is also common. Among options, dnsrecon is correct and typical.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse general DNS queries (like `dig ANY` or `nslookup -type=ns`) with the specific zone transfer request (AXFR), assuming any DNS enumeration command can retrieve the full zone file.
Detailed technical explanation
How to think about this question
DNS zone transfer (AXFR) is defined in RFC 1034 and 1035 and allows a secondary DNS server to replicate the entire zone file from a primary server. In practice, many DNS servers are misconfigured to allow AXFR from any host, making this a powerful reconnaissance technique; a successful transfer reveals all hostnames, IP addresses, and even hidden services. The `dnsrecon` tool automates this check and can also perform other enumeration techniques like SRV record queries or brute-forcing if AXFR fails.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
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.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this CEH question in full detail.
Footprinting, Reconnaissance and Scanning — This question tests Footprinting, Reconnaissance and Scanning — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: dnsrecon -d example.com -t axfr — Option D is correct because the `-t axfr` flag in `dnsrecon` specifically attempts a DNS zone transfer (AXFR query) against the target domain's authoritative nameservers. A successful zone transfer returns all DNS records, including all subdomains, making it the most direct and effective method for subdomain enumeration via DNS zone transfer.
What should I do if I get this CEH question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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