- A
let entropy_threshold = 4.0; let length_threshold = 20; CommonSecurityLog | where DeviceVendor == "Palo Alto" | extend entropy = strlen(DestinationHostName) - countof(DestinationHostName, 'a', 'z') / strlen(DestinationHostName) | where entropy > entropy_threshold or strlen(DestinationHostName) > length_threshold
Entropy and length thresholds help detect random-looking DGA domains.
- B
CommonSecurityLog | where DestinationHostName !endswith ".com"
Why wrong: Filtering out .com domains is not specific to DGA; many legitimate non-.com domains exist.
- C
CommonSecurityLog | where DestinationHostName in (dynamic_threat_intel_list)
Why wrong: This relies on pre-existing threat intelligence, not dynamic hunting for unknown DGA.
- D
CommonSecurityLog | where DeviceVendor == "Palo Alto" | summarize count() by DestinationHostName | top 10 by count_
Why wrong: This only shows top domains by volume, not randomness indicative of DGA.
Quick Answer
The correct KQL query for DNS tunneling detection with entropy is Option B, which calculates entropy and length to identify algorithmically generated domains. This query works by computing the ratio of random characters in the domain name—specifically, it uses `strlen(DestinationHostName) - countof(DestinationHostName, 'a', 'z') / strlen(DestinationHostName)` to measure character diversity, then flags domains where entropy exceeds 4.0 or length exceeds 20 characters. On the SC-200 exam, this tests your ability to distinguish between dynamic analysis of domain randomness and static methods like threat intelligence lookups or simple frequency counts. A common trap is choosing Option A, which only lists top domains by count and misses low-volume but high-entropy tunneling domains. For the exam, remember that DNS tunneling domains are long and random, not just numerous—think "length and entropy, not frequency." A useful memory tip: "High entropy, long string—that’s your tunneling thing."
SC-200 Perform threat hunting Practice Question
This SC-200 practice question tests your understanding of perform threat hunting. 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.
During a threat hunt, you notice an unusual number of DNS queries for randomly generated subdomains from a single workstation. You suspect data exfiltration via DNS tunneling. Which KQL query in Microsoft Sentinel would best help you identify the suspicious domain names?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"best"Why it matters: Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
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
let entropy_threshold = 4.0; let length_threshold = 20; CommonSecurityLog | where DeviceVendor == "Palo Alto" | extend entropy = strlen(DestinationHostName) - countof(DestinationHostName, 'a', 'z') / strlen(DestinationHostName) | where entropy > entropy_threshold or strlen(DestinationHostName) > length_threshold
Option B is correct because it calculates entropy and length to detect algorithmically generated domains, a common indicator of DNS tunneling. Option A is wrong because it only lists top domains by count, not randomness. Option C is wrong because it filters non-.com domains, missing many DGA domains. Option D is wrong because it queries a static threat intelligence list, not dynamic analysis.
Key principle: NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
let entropy_threshold = 4.0; let length_threshold = 20; CommonSecurityLog | where DeviceVendor == "Palo Alto" | extend entropy = strlen(DestinationHostName) - countof(DestinationHostName, 'a', 'z') / strlen(DestinationHostName) | where entropy > entropy_threshold or strlen(DestinationHostName) > length_threshold
Why this is correct
Entropy and length thresholds help detect random-looking DGA domains.
Clue confirmation
The clue word "best" in the question point toward this answer.
Related concept
Static NAT maps one inside address to one outside address.
- ✗
CommonSecurityLog | where DestinationHostName !endswith ".com"
Why it's wrong here
Filtering out .com domains is not specific to DGA; many legitimate non-.com domains exist.
- ✗
CommonSecurityLog | where DestinationHostName in (dynamic_threat_intel_list)
Why it's wrong here
This relies on pre-existing threat intelligence, not dynamic hunting for unknown DGA.
- ✗
CommonSecurityLog | where DeviceVendor == "Palo Alto" | summarize count() by DestinationHostName | top 10 by count_
Why it's wrong here
This only shows top domains by volume, not randomness indicative of DGA.
Common exam traps
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Trap categories for this question
Command / output trap
This only shows top domains by volume, not randomness indicative of DGA.
Detailed technical explanation
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
- Static NAT maps one inside address to one outside address.
- PAT allows many inside hosts to share one public address using ports.
- Inside local and inside global describe the private and translated addresses.
- NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
- Identify inside and outside interfaces first.
- Check whether the scenario needs static NAT, dynamic NAT or PAT.
- Do not confuse NAT matching ACLs with normal packet-filtering intent.
Key takeaway
NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Real-world example
How this comes up in practice
A cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.
What to study next
Got this wrong? Here's your next step.
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related SC-200 NAT questions on configuration and troubleshooting.
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Perform threat hunting — study guide chapter
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Perform threat hunting practice questions
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FAQ
Questions learners often ask
What does this SC-200 question test?
Perform threat hunting — This question tests Perform threat hunting — Static NAT maps one inside address to one outside address..
What is the correct answer to this question?
The correct answer is: let entropy_threshold = 4.0; let length_threshold = 20; CommonSecurityLog | where DeviceVendor == "Palo Alto" | extend entropy = strlen(DestinationHostName) - countof(DestinationHostName, 'a', 'z') / strlen(DestinationHostName) | where entropy > entropy_threshold or strlen(DestinationHostName) > length_threshold — Option B is correct because it calculates entropy and length to detect algorithmically generated domains, a common indicator of DNS tunneling. Option A is wrong because it only lists top domains by count, not randomness. Option C is wrong because it filters non-.com domains, missing many DGA domains. Option D is wrong because it queries a static threat intelligence list, not dynamic analysis.
What should I do if I get this SC-200 question wrong?
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related SC-200 NAT questions on configuration and troubleshooting.
Are there clue words in this question I should notice?
Yes — watch for: "best". Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
What is the key concept behind this question?
Static NAT maps one inside address to one outside address.
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Last reviewed: Jun 21, 2026
This SC-200 practice question is part of Courseiva's free Microsoft 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 SC-200 exam.
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