Bounceback starttls is required to send mail

A very specific and technical question!

bounceback is a feature in some email servers that allows them to send a bounce message (also known as a non-delivery report or NDR) to the sender when an email cannot be delivered to the recipient. This is useful for debugging and troubleshooting email delivery issues.

starttls is a protocol extension to the SMTP (Simple Mail Transfer Protocol) that allows for the encryption of the communication between email servers. It's commonly used to secure the transmission of email messages.

When you need to send mail using bounceback, you typically need to use starttls as well. This is because bounceback relies on the ability to send email messages to the sender, and starttls ensures that the communication between the email servers is encrypted and secure.

Here's a breakdown of the requirements:

1. bounceback is required to send a bounce message to the sender when an email cannot be delivered.
2. starttls is required to encrypt the communication between email servers, which is necessary for secure email transmission.
3. Both bounceback and starttls are typically used together to ensure that email messages are delivered securely and that bounce messages are sent to the sender when necessary.

In summary, bounceback and starttls are both important features in email transmission, and they are often used together to ensure secure and reliable email delivery.