The answer is an abrupt client disconnect before the MySQL handshake completes. This is the most likely cause because the 'Aborted connection' warning in RDS MySQL specifically triggers when a client opens a TCP connection to the database but then closes it—or the network drops it—before the MySQL server finishes the authentication and session initialization phase. On the AWS Certified Database Specialty DBS-C01 exam, this scenario tests your understanding of MySQL connection lifecycle events versus network timeouts; a common trap is confusing this with `wait_timeout` or `max_connect_errors`, which involve fully established connections. The key differentiator is that the error log message will read "Got an error reading communication packets," pointing to a broken handshake rather than a slow query or idle session. Memory tip: think "handshake hang-up"—if the client walks away before shaking hands, the server logs an aborted connection, not a timeout.
DBS-C01 Management and Operations Practice Question
This DBS-C01 practice question tests your understanding of management and operations. 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.
Exhibit
Refer to the exhibit.
Exhibit: Amazon RDS for MySQL error log snippet
```
2023-06-01 10:00:00 1234567890 [Warning] Aborted connection 1234567890 to db: 'mydb' user: 'appuser' host: '10.0.0.50' (Got an error reading communication packets)
```
A database administrator sees repeated 'Aborted connection' warnings in the RDS for MySQL error log. The application team reports intermittent connection errors. What is the most likely cause of these aborted connections?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Refer to the exhibit.
Exhibit: Amazon RDS for MySQL error log snippet
```
2023-06-01 10:00:00 1234567890 [Warning] Aborted connection 1234567890 to db: 'mydb' user: 'appuser' host: '10.0.0.50' (Got an error reading communication packets)
```
A
The wait_timeout parameter is too low, causing idle connections to be terminated.
Why wrong: If wait_timeout kills idle connections, the error would be different.
B
The user 'appuser' does not have permission to connect from host '10.0.0.50'.
Why wrong: That would cause an authentication error, not an aborted connection due to communication packets.
C
The database instance is running out of memory, causing connection drops.
Why wrong: Out-of-memory issues would cause different symptoms.
D
The application is closing the database connection abruptly without completing the handshake.
Aborted connections often occur when the client disconnects before finishing the login handshake, which is a common application bug.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The application is closing the database connection abruptly without completing the handshake.
The error 'Got an error reading communication packets' typically indicates a network issue or the client disconnecting unexpectedly. The most common cause is that the database connection is being closed by the application without properly closing the connection, or the network between the application and database is unstable. Option C is plausible but less likely because the error message points to communication issues.
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
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
The wait_timeout parameter is too low, causing idle connections to be terminated.
Why it's wrong here
If wait_timeout kills idle connections, the error would be different.
✗
The user 'appuser' does not have permission to connect from host '10.0.0.50'.
Why it's wrong here
That would cause an authentication error, not an aborted connection due to communication packets.
✗
The database instance is running out of memory, causing connection drops.
Why it's wrong here
Out-of-memory issues would cause different symptoms.
✓
The application is closing the database connection abruptly without completing the handshake.
Why this is correct
Aborted connections often occur when the client disconnects before finishing the login handshake, which is a common application bug.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Static NAT maps one inside address to one outside address.
Common exam traps
Common exam trap: NAT rules depend on direction and matching traffic
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
How to think about this question
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.
KKey Concepts to Remember
Static NAT maps one inside address to one outside address.
PAT allows many inside hosts to share one public address using ports.
Inside local and inside global describe the private and translated addresses.
NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
→Identify inside and outside interfaces first.
→Check whether the scenario needs static NAT, dynamic NAT or PAT.
→Do not confuse NAT matching ACLs with normal packet-filtering intent.
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
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.
What to study next
Got this wrong? Here's your next step.
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 DBS-C01 NAT questions on configuration and troubleshooting.
Management and Operations — This question tests Management and Operations — Static NAT maps one inside address to one outside address..
What is the correct answer to this question?
The correct answer is: The application is closing the database connection abruptly without completing the handshake. — The error 'Got an error reading communication packets' typically indicates a network issue or the client disconnecting unexpectedly. The most common cause is that the database connection is being closed by the application without properly closing the connection, or the network between the application and database is unstable. Option C is plausible but less likely because the error message points to communication issues.
What should I do if I get this DBS-C01 question wrong?
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 DBS-C01 NAT questions on configuration and troubleshooting.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Static NAT maps one inside address to one outside address.
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