Which combination of actions should a SysOps administrator take so that the web servers can communicate with the DB instance?

A company website contains a web tier and a database tier on AWS. The web tier consists of Amazon EC2 instances that run in an Auto Scaling group across two Availability Zones. The database tier runs on an Amazon ROS for MySQL Multi-AZ DB instance. The database subnet network ACLs are restricted to only the web subnets that need access to the database. The web subnets use the default network ACL with the default rules.

The company’s operations team has added a third subnet to the Auto Scaling group configuration. After an Auto Scaling event occurs, some users report that they intermittently receive an error

message. The error message states that the server cannot connect to the database. The operations team has confirmed that the route tables are correct and that the required ports are open on all security groups.

Which combination of actions should a SysOps administrator take so that the web servers can communicate with the DB instance? (Select TWO.)
A . On the default ACL. create inbound Allow rules of type TCP with the ephemeral port range and the source as the database subnets.
B . On the default ACL, create outbound Allow rules of type MySQL/Aurora (3306). Specify the destinations as the database subnets.
C . On the network ACLs for the database subnets, create an inbound Allow rule of type MySQL/Aurora (3306). Specify the source as the third web subnet.
D . On the network ACLs for the database subnets, create an outbound Allow rule of type TCP with the ephemeral port range and the destination as the third web subnet.
E . On the network ACLs for the database subnets, create an outbound Allow rule of type MySQL/Aurora (3306). Specify the destination as the third web subnet.

View Answer

Answer: CD

Explanation:

To ensure that the new web subnet can communicate with the database instance, follow these steps:

Create an Inbound Allow Rule for MySQL/Aurora (3306):

On the network ACL for the database subnets, add an inbound allow rule to permit traffic from the third web subnet on port 3306 (MySQL/Aurora).

Reference: Network ACLs

Create an Outbound Allow Rule for Ephemeral Ports:

On the network ACL for the database subnets, add an outbound allow rule to permit traffic to the third web subnet on the ephemeral port range (1024-65535).

Reference: Ephemeral Ports

These changes will ensure that the new subnet can communicate with the database, resolving the connectivity issues.