How does AWS monitor our use of outbound port 25?

Question

If we are sending SMTP checks to email addressee that do not exist, does this look the same to AWS as if we were sending a full email that bounces?

Answer 1

From Remove port 25 restriction from your EC2 instance:

AWS blocks outbound traffic on port 25 (SMTP) of all EC2 instances and Lambda functions by default. If you want to send outbound traffic on port 25, you can request for this restriction to be removed.