Default Database Ports for AWS RDS Engines
Network Topology
Refer to the exhibit. A developer wants to connect to the database. Which database engine is most likely being used?
Quick Answer
The answer is MySQL, as the exhibit shows port 3306, which is the default database port for Amazon RDS MySQL and MariaDB engines. This is because AWS RDS assigns a standard TCP port to each supported database engine upon instance creation, and port 3306 is the well-known default for MySQL-based services, including Aurora MySQL when configured with RDS-style endpoints. On the AWS Certified Database Specialty DBS-C01 exam, this concept tests your ability to quickly identify an engine from connection metadata, often appearing in scenario-based questions where a developer provides a port number or endpoint snippet. A common trap is confusing port 3306 with PostgreSQL (5432) or Oracle (1521), especially when MariaDB is an option—remember that MariaDB shares MySQL’s default port. For a quick memory tip: think of MySQL’s “3306” as “three-three-zero-six, the MySQL fix”—it’s the only major RDS engine using that port, so when you see it, lock in MySQL or MariaDB.
⚠ Common exam trap
The DBS-C01 exam often tests the ability to identify database engines by their JDBC connection string prefixes, and the trap here is that candidates may confuse MySQL with PostgreSQL or Oracle because all are relational databases, but each has a distinct JDBC URL format that must be matched exactly.
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
✓
MySQL
The exhibit shows a connection string using the format `jdbc:mysql://...`, which is the standard JDBC URL prefix for MySQL databases. This indicates the developer is connecting to a MySQL database engine, as Oracle, SQL Server, and PostgreSQL use different JDBC URL prefixes (`jdbc:oracle:thin:`, `jdbc:sqlserver://`, and `jdbc:postgresql://` respectively).
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Oracle
Why it's wrong here
Oracle uses port 1521.
- ✗
SQL Server
Why it's wrong here
SQL Server uses port 1433.
- ✓
MySQL
Why this is correct
Port 3306 is default for MySQL.
- ✗
PostgreSQL
Why it's wrong here
PostgreSQL uses port 5432.
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Same concept, more angles
1 more way this is tested on DBS-C01
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. Match each database engine to its default port number.
medium- ✓ A.MySQL: 3306
- ✓ B.PostgreSQL: 5432
- ✓ C.Oracle: 1521
- ✓ D.SQL Server: 1433
- E.MySQL: 5432
- F.PostgreSQL: 3306
Why A: The default ports are: MySQL on 3306, PostgreSQL on 5432, Oracle on 1521, and SQL Server on 1433. Common confusions include swapping MySQL and PostgreSQL ports.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DBS-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 DBS-C01 exam.