[Users] How to hide sender IP address and host name?

[Removed GDPR]

> Within your emails the sender address and the IP address so that the
> mail will pass a number of spam filters.
> While you consider it unwarranted disclosure, others require it to
> allow the email to pass.

But the mail passes based on MX, SPF (whitelisting server IP address)
and DKIM, not based on the personal IP address of the mail client
(which doesn't exist in the server or domain configuration).