350-701 Network Security Practice Question
A Cisco FTD sensor is deployed in passive mode (IDS) and is receiving traffic via a network tap. The access control policy is configured with an intrusion policy set to 'Security over Connectivity'. However, the administrator notices that the sensor is not generating alerts for some attacks that were identified by a previous inline sensor. What is the most likely reason?
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
✓
The sensor is in passive mode and cannot see return traffic due to asymmetric routing.
In passive mode, the sensor cannot block traffic, but it should still detect and alert. If it's not alerting, perhaps the traffic is not being seen correctly (e.g., due to asymmetric routing or tap issues) or the intrusion policy is not applied correctly. However, given the scenario, a common issue is that passive deployment can miss attacks if traffic is not visible to the sensor.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
The sensor is in passive mode and cannot see return traffic due to asymmetric routing.
Why this is correct
Correct. Passive sensors rely on seeing both directions of traffic; asymmetric routing can cause missed detections.
- ✗
The access control policy requires an 'allow' action to perform intrusion inspection.
Why it's wrong here
Incorrect. In passive mode, the sensor inspects all traffic regardless of action.
- ✗
The intrusion policy is set to 'Security over Connectivity', which reduces false positives but may miss some attacks.
Why it's wrong here
Incorrect. 'Security over Connectivity' increases sensitivity, not reduces.
- ✗
The intrusion policy is not configured to generate alerts.
Why it's wrong here
Incorrect. Intrusion policy by default generates alerts.
Quick reference
Asymmetric Encryption Algorithm Comparison
| Algorithm | Key Exchange | Signatures | Equivalent Security Key | Notes |
|---|---|---|---|---|
| RSA-3072 | Yes | Yes | 128-bit | Widely deployed; slow for bulk data |
| ECDSA P-256 | No | Yes | 128-bit | Fast signatures; standard TLS certs |
| ECDH / ECDHE | Yes | No | 128-bit | Perfect forward secrecy in TLS 1.3 |
| DH / DHE | Yes | No | 128-bit (3072-bit key) | Replaced by ECDHE in modern TLS |
| Ed25519 | No | Yes | ~128-bit | SSH keys, modern PKI |
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 350-701 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 350-701 exam.