This plugin is informational and will merely add headers to each incoming message:
- X-MAIL-FROM: The SMTP envelope sender address.
- X-RCPT-TO: The recipient(s) of the message.
- X-HELO: The HELO/EHLO name used by the connecting client.
- X-REMOTE-IP: The IP address the connection was made from.
- X-REMOTE-HOST: The hostname of that IP address, if any.