[exim] User allow-lists

[ Prompted by a question to the alpine support email list. ]

Non-personal correspondents (mailing-lists, corporates etc.)
sometimes ask you to to allow-list (aka want-list or white-list)
their address when you sign up to receive emails from them.

The big players with their webmail and integrated apps
allow users to do this through the MUA.

In your exim mail system do you allow users to allow-list senders,
and if so how ?

Thanks,

-- 
Andrew C. Aitchison                      Kendal, UK
                    andrew@???

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