Re: Who should set the Sender: header field?

On Mon 13/Dec/2021 20:24:52 +0100 John Levine wrote:
> It appears that Alessandro Vesely  <[email protected]> said:
>>using Thunderbird, for one, it is easy to modify the From: field of the message 
>>being edited, possibly setting multiple mailboxes.  However, that software 
>>omits to add a Sender: field, which is required in such cases.  Where's the 
>>bug?  Options are:
>>
>>* The MUA should prompt for a Sender:, or
> 
> How very annoying for the 99% of cases where the sender would be
> redundant with the from.


Of course, I meant only in case the user added multiple mailboxes to From:. 
RFC 5322 requires that a Sender: field be there in such cases.


>>* the submission server adds Sender according to the logged-in identity.
> 
> Sorry, but submission servers are not the source of truth for someone's "real"
> email address, much less their identity.  I have hundreds of e-mail addresses.
> All of them are me, and I would not appreciate some piece of software picking
> one arbitrarily and adding a sender header to my mail.


Agreed.  Perhaps there should be a per-user configuration option to tell the 
preferred Sender: to be set when it's missing and required.  Otherwise, picking 
the first compatible mailbox of From: could be a good default.


> On my system, the submission server puts the submission account, which
> is not necessarily an email address, in the Received header in case
> there is some need to figure out where a message came from.


On mine, I obscure the Received:'s AUTH token to prevent leaking such info.


>>I realize that both might take care of that, but where should I file a bug first?
> 
> Nowhere, please.  If for some reason you want to add a sender header, there are
> plugins like Header Tools which let you do so.


So you point to the client...

However, I only found a "Header Tools Lite" for Thunderbird, which seems to be 
designed to change the header of /received/ messages, not outgoing ones.


Best
Ale
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