Feature wishlist: Allow to hide client IP/host in submission service

[Tom Sommer]

On 2019-08-25 20:51, Sebastian Krause via dovecot wrote:
> Hi,
> 
> In many mail setups a required feature (for privacy reasons) is to
> hide the host and IP of clients (in the "Received" header) that use
> the authenticated submission over port 587. In Postfix that's
> possible (https://serverfault.com/q/413533/86332), but not very nice
> to configure especially if you only want want to strip the Received
> header for port 587 submissions, but not on port 25.
> 
> As far as I can see this configuration is not possible at all in the
> Dovecot submission server because the function which adds the
> Received header with the client's IP address
> (smtp_server_transaction_write_trace_record) is always called in
> submission-commands.c.
> 
> It would be very useful if the submission server could anonymize the
> client with a single configuration option, then all the Postfix
> configuration mess (and using SASL) could be skipped by simply using
> the Dovecot submission server instead.
> 
> The anonymization would work by replacing the client's EHLO host
> with "submission" and the IP address with 127.0.0.1. In full the
> Received header would look something like this where the first line
> is always the same:
> 
> Received: from submission (unknown [127.0.0.1])
>    by mail.example.com with ESMTPSA
>    id 8bV9D+51Yl1FOwAA1ctoJQ
>    (envelope-from <john at example.com>)
>    for <jane at example.com>; Sun, 25 Aug 2019 13:50:06 +0200

Check https://github.com/dovecot/core/pull/74

Unsure if it covers Submission though