200-201 Security Monitoring Practice Question
An analyst suspects a host is communicating with a command-and-control server using DNS tunneling. Which THREE network traffic patterns would support this hypothesis?
⚠ Common exam trap
200-201 often tests the ability to distinguish between normal DNS behavior and malicious patterns, where candidates might overlook the significance of TXT records and large response sizes in favor of less specific indicators like TTL values.
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
✓
Frequent use of TXT record type in DNS queries
Option A is correct because DNS tunneling often abuses TXT records, which can carry arbitrary text payloads, to exfiltrate data or receive commands from a C2 server. Option B is correct because tunneling responses frequently contain encoded data, making DNS responses larger than the typical small A-record response. Option E is correct because a single host generating a high volume of DNS queries to one domain is a classic beaconing/tunneling indicator. Option C is not correct because high TTL values are not characteristic of DNS tunneling; tunneling often uses low or zero TTLs to avoid caching. Option D is not correct because queries to multiple well-known domains are common benign behavior and do not specifically indicate DNS tunneling.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Frequent use of TXT record type in DNS queries
Why this is correct
DNS tunnelling exfiltrates data by encoding payloads into DNS queries and responses, and TXT records carry arbitrary text up to 255 characters per string, making them the preferred carrier. Frequent TXT queries to a single domain, especially with high entropy or long labels, satisfy the stem's command-and-control hypothesis.
- ✓
DNS response sizes larger than typical A record responses
Why this is correct
Tunnelling embeds data in responses, inflating them well beyond the small, predictable size of a normal A record answer. Abnormally large DNS responses therefore signal encoded payloads moving from the command-and-control server to the compromised host.
- ✗
DNS queries with TTL values greater than 86400
Why it's wrong here
High TTL is not typical for tunneling.
- ✗
DNS queries for multiple well-known domains
Why it's wrong here
Queries to multiple well-known domains describe ordinary browsing or CDN resolution, not tunnelling. Tunnelling concentrates traffic on one or few attacker-controlled domains carrying encoded payloads. This pattern would instead support a benign-traffic baseline hypothesis during anomaly triage.
- ✓
High volume of DNS queries from a single host to a single domain
Why this is correct
A single internal host generating a disproportionately high volume of DNS queries to one domain indicates data exfiltration or command retrieval over DNS. Legitimate resolvers distribute queries across many domains; tunnelling concentrates them on one authoritative server, satisfying the stem's requirement for traffic patterns supporting DNS tunnelling.
Visual reference
Go deeper
Related to this question
About these practice questions
One of 968 original 200-201 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Cisco exam blueprint
This 200-201 practice question is part of Courseiva's free Cisco 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 200-201 exam.