Re: [Fetchmail-users] XCLIENT and CLIENTID extensions to SMTP

[Matthias A. <mat...@gm...>]

Am 23.03.23 um 11:55 schrieb Andrew C Aitchison:
> I have become aware of two extensions to SMTP (and one to IMAP too)
> that may be of interest to fetchmail developers and users.
>
> The first is https://www.postfix.org/XCLIENT_README.html
> which says that
>    The XCLIENT command targets the following problems:
>    ...        ...        ...
>    2. Client software that downloads mail from an up-stream mail server and
>    injects it into a local MTA via SMTP. In order to take advantage of the
>    local MTA's SMTP server access rules, the client software needs the
>    ability to override the SMTP server's idea of the remote client name,
>    client address and other information. Such information can typically be
>    extracted from the up-stream mail server's Received: message header.
>
> XCLIENT is implemented in postfix and is now a wishlist item for Exim:
> https://bugs.exim.org/show_bug.cgi?id=2702 as well as being available
> in a fork of Exim (
> https://github.com/SpamExperts/exim/commit/3798d48d73c89f7835726d31f096851f7f7fca2a ).
>
> The second is CLIENTID, a pair of draft RFCs
> https://datatracker.ietf.org/doc/draft-storey-smtp-client-id/
> https://datatracker.ietf.org/doc/draft-yu-imap-client-id/
> which allows the mail client to tell the server more about itself
> and the user, allowing a server to restrict access on a device+user basis;
> eg to block a spammer who has got hold of your login details, whilst
> continuing to allowing you to send and receive emails from your phone.
>
> CLIENTID is supported by Thunderbird, emClient, and BlueMail clients
> and at least MagicMail "the Top Selling Carrier Grade Email platform for
> the ISP, Telco, and Cable industry in North America".
> I am currently attempting to write CLIENTID support for Exim.

Andrew,

Thank you. I had thought about this in the past, but not added it, and I
find your context presentation valuable. I have thus filed this under
https://gitlab.com/fetchmail/fetchmail/-/issues/58

...so it's with the other feature requests.

Thanks for your suggestion!

Cheers,
Matthias