Implementing a header firewall

When messages are passed from one server to another through SMTP, Exchange Edge, and Mailbox servers, add custom X-Header fields are added to the message header. These headers can contain a variety of information, such as mail server IP addresses, spam confidence levels (SCL), content filtering results, and rule processing statuses. Header firewalls are used to remove these custom X-Header fields so that unauthorized sources cannot obtain detailed information about your messaging environment. In this recipe, you'll learn how to use the Exchange Management Shell to implement a header firewall that prevents the disclosure of internal information sent to an external source.

How to do it...

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