mail() Function in PHP and Bounced E-Mails

Everyone’s favorite way of sending spam is the mail() function in PHP. The question of the day is what happens to the bounced e-mails that may result from this operation.

No, they’re not necessarily sent back to the “From” address of the original message. Mail servers return undeliverable messages to the envelope sender, which may or may not match the “From” field. There used to be a special header, Errors-To, but it was deprecated and as of today that is often ignored.