Quick Answer
The answer is the action field, because VPC Flow Logs record whether traffic was ACCEPTED or REJECTED in that specific field, making it the only place to directly identify rejected packets for troubleshooting connectivity issues. When you filter flow log records for REJECT in the action field, you isolate exactly the traffic that failed security group or network ACL rules, which is the core diagnostic step for blocked connections. On the AWS Certified Advanced Networking Specialty ANS-C01 exam, this concept often appears in scenario-based questions where you must distinguish between the action field and other fields like srcaddr, dstport, or protocol—common traps that test whether you know that source IPs or ports alone cannot reveal a rejection decision. A reliable memory tip is to think of the action field as the verdict: it tells you if the packet was let through or turned away, while every other field only describes the packet’s characteristics.
This ANS-C01 practice question tests your understanding of network security, compliance and governance. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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.
A network engineer runs the above command and sees that VPC Flow Logs are configured for a VPC. The engineer wants to analyze rejected traffic to troubleshoot a connectivity issue. Which field in the flow log records should they examine?
protocol
Why wrong: Protocol number, not action.
action
Shows whether traffic was accepted or rejected.
srcaddr
Why wrong: Source address, not action.
dstport
Why wrong: Destination port, not action.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
action
Option B is correct because the 'action' field in VPC Flow Logs indicates ACCEPT or REJECT. Option A is wrong because 'srcaddr' is source IP. Option C is wrong because 'dstport' is destination port. Option D is wrong because 'protocol' is the protocol number.
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
For each option: why learners choose it and why it is or isn't the right answer here.
protocol
Why it's wrong here
Protocol number, not action.
action
Why this is correct
Shows whether traffic was accepted or rejected.
Related concept
Static NAT maps one inside address to one outside address.
srcaddr
Why it's wrong here
Source address, not action.
dstport
Why it's wrong here
Destination port, not action.
Common exam traps
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.
Detailed technical explanation
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.
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
A healthcare organisation deploys an application with a public-facing web tier and a private database tier. The database subnet has no public IP and only accepts connections from the web tier's security group. Questions like this test whether you can design cloud network isolation using VNets/VPCs, subnets, and security group rules.
What to study next
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 ANS-C01 NAT questions on configuration and troubleshooting.
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FAQ
Network Security, Compliance and Governance — This question tests Network Security, Compliance and Governance — Static NAT maps one inside address to one outside address..
The correct answer is: action — Option B is correct because the 'action' field in VPC Flow Logs indicates ACCEPT or REJECT. Option A is wrong because 'srcaddr' is source IP. Option C is wrong because 'dstport' is destination port. Option D is wrong because 'protocol' is the protocol number.
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 ANS-C01 NAT questions on configuration and troubleshooting.
Static NAT maps one inside address to one outside address.
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Last reviewed: Jun 20, 2026
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.
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