The correct answer is to add a `where` clause to exclude known internal DNS server IPs. This approach directly addresses the core challenge of refining DNS query hunting by filtering out the high-volume, legitimate traffic that drowns out suspicious activity, allowing you to focus on anomalous endpoints rather than infrastructure noise. On the Microsoft Security Operations Analyst SC-200 exam, this tests your ability to tune KQL queries in Microsoft Defender XDR for precision—a common trap is to increase the query threshold, which risks missing real attacks, or to overcomplicate the query with unnecessary joins. Remember that legitimate DNS servers are predictable, so excluding their IPs is the most efficient filter, while changing the port to 53 is redundant since DNS already uses it. Memory tip: think "Exclude the noise, keep the anomalies"—a simple `where` clause on IPs is your sharpest scalpel.
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.
Exhibit
{
"QueryText": "DeviceNetworkEvents | where RemotePort == 53 and Timestamp > ago(1d) | summarize count() by DeviceName, RemoteIP | where count_ > 1000",
"QueryDescription": "Hunt for potential DNS amplification attacks from internal devices"
}
Refer to the exhibit. You are using a hunting query in Microsoft Defender XDR to find devices generating excessive DNS queries. The query returns many results, but you want to exclude legitimate DNS servers. What is the best approach to refine the query?
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.
{
"QueryText": "DeviceNetworkEvents | where RemotePort == 53 and Timestamp > ago(1d) | summarize count() by DeviceName, RemoteIP | where count_ > 1000",
"QueryDescription": "Hunt for potential DNS amplification attacks from internal devices"
}
A
Add a `where` clause to exclude known internal DNS server IPs.
Excluding known DNS servers reduces noise from legitimate traffic.
B
Join with DeviceInfo to filter by device type.
Why wrong: Device type may not help; DNS servers could be on any device.
C
Change the RemotePort filter to UDP 53 only instead of all DNS.
Why wrong: DNS uses UDP 53 typically; adding TCP 53 would catch more, not less.
D
Increase the count threshold to 5000.
Why wrong: Adjusting threshold may miss low-volume attacks.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Add a `where` clause to exclude known internal DNS server IPs.
Option C is correct because filtering out known DNS server IPs reduces false positives. Option A is wrong because changing the port to 53 is already done. Option B is wrong because increasing the threshold may miss real attacks. Option D is wrong because joining with identity info is unnecessary and may not help.
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.
✓
Add a `where` clause to exclude known internal DNS server IPs.
Why this is correct
Excluding known DNS servers reduces noise from legitimate traffic.
Clue confirmation
The clue word "best" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
Join with DeviceInfo to filter by device type.
Why it's wrong here
Device type may not help; DNS servers could be on any device.
✗
Change the RemotePort filter to UDP 53 only instead of all DNS.
Why it's wrong here
DNS uses UDP 53 typically; adding TCP 53 would catch more, not less.
✗
Increase the count threshold to 5000.
Why it's wrong here
Adjusting threshold may miss low-volume attacks.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
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.
Use explanations to understand the rule behind the answer.
TExam Day Tips
→Underline the problem statement mentally.
→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 company's IT admin needs to give a contractor read-only access to production logs without sharing account credentials. Using role-based access control (RBAC) and temporary scoped permissions — not a permanent shared password — is the correct pattern. Questions like this test whether you can apply least-privilege access across cloud identity services.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this SC-200 question in full detail.
Identify which SC-200 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Perform threat hunting — This question tests Perform threat hunting — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Add a `where` clause to exclude known internal DNS server IPs. — Option C is correct because filtering out known DNS server IPs reduces false positives. Option A is wrong because changing the port to 53 is already done. Option B is wrong because increasing the threshold may miss real attacks. Option D is wrong because joining with identity info is unnecessary and may not help.
What should I do if I get this SC-200 question wrong?
Identify which SC-200 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
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?
Read the scenario before looking for a memorised answer.
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