AWS Certified Advanced Networking – Specialty (ANS-C00) — Question 357

You wish to host a mailserver on an EC2 instance. What two steps must you take to ensure utmost reliability?

Answer options

• A. Create an EIP for the instance.
• B. Configure the mail service to serve as an open relay.
• C. Contact AWS to have a Reverse DNS record configured and to help keep your domain from SPAM blacklists.
• D. Provide open security group access to your instance on ports 25, 3389 and 22.

Correct answer: A, C

Explanation

An Elastic IP (EIP) ensures the mail server maintains a persistent, static public IP address, which is crucial for consistent mail delivery. Requesting AWS to configure a Reverse DNS (rDNS) record and remove email sending limits prevents outgoing emails from being flagged as SPAM by recipient servers. Configuring an open relay (Option B) or exposing administrative ports like 22 and 3389 globally (Option D) would compromise security and lead to blacklisting.