[MlMt] Really weird bug--mail sent from wrong account

[Bill Cole]

On 22 Sep 2016, at 5:00, Benny Kjær Nielsen wrote:

> On 22 Sep 2016, at 6:56, Kee Hinckley wrote:
[...]
>> The dangerous thing is that Google SMTP doesn't reject the message 
>> for being from an unknown account--it changes the headers.
>
> I also consider that a bug, but I guess Google does not see it that 
> way.

There are reasons that there is not much spam coming out of GMail 
servers but LOTS coming out of Yahoo and Microsoft. This is one of them: 
GMail "corrects" the From header and envelope sender address to match 
the authenticated sender. ISTR there is or was some way to add addresses 
(with a confirmation cycle) that would pass in the From header for an 
account, but the envelope sender would still be "corrected." Since the 
advent of DMARC, I would expect that feature to be gone (since DMARC 
deals with headers, not the envelope.)