ANS-C01 Network Management and Operations Practice Question
A company uses AWS Direct Connect with a private virtual interface (VIF) to connect its on-premises network to its VPC. The on-premises network team reports that they can ping the private IP address of an EC2 instance in the VPC, but cannot establish a TCP connection to a web server running on that instance. The network security group allows inbound TCP port 80 from the on-premises CIDR. What should the network engineer check next?
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
✓
Check the operating system firewall and web server configuration on the EC2 instance.
The instance's OS firewall or web server configuration may be blocking the TCP connection, even though ping works (ICMP may be allowed). Option A is wrong because ping works, indicating routing and NACL are fine. Option C is wrong because the BGP session status is unrelated to connectivity to the instance. Option D is wrong because the NACL is stateless and would affect ping as well, so routing is fine.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Review the network ACL associated with the subnet to ensure it allows inbound TCP 80.
Why it's wrong here
NACL would affect ping too if it were blocking.
- ✓
Check the operating system firewall and web server configuration on the EC2 instance.
Why this is correct
The OS firewall or application may block TCP despite security group allowing it.
- ✗
Check the BGP session status on the Direct Connect virtual interface.
Why it's wrong here
BGP is not related to TCP connectivity to the instance.
- ✗
Verify the route table on the VPC has a route back to the on-premises network.
Why it's wrong here
Ping works, so routing is functional.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This ANS-C01 practice question is part of Courseiva's free Amazon Web Services 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 ANS-C01 exam.