[MlMt] Return-Path when sending message using an alias

[Bill Cole]

On 30 Mar 2021, at 1:57, Tom Kerswill wrote:

> When I use mailmate to 'send as' one of these addresses, Gmail rejects 
> it.
> When I look at the headers of that sent mail, they are different from
> messages sent by other mail clients or Gmail itself. The messages from
> mailmate do have the correct from address, but my actual Gmail address 
> also
> appears to be there as a Return-Path header.

That is NOT being done by MailMate. I have confirmed by testing just now 
that when MailMate sends mail from an address that is not the main one 
for an account, it uses the secondary address as the SMTP envelope 
sender, which is normally where the Return-Path header on delivered mail 
comes from. GMail is apparently using your authentication address 
instead, which is perverse.

I am curious about what is actually happening with your mail, since if 
GMail is rejecting it outright I would expect you to have nothing to 
look at with a 'wrong' Return-Path. Are they accepting it initially and 
then generating a bounce message? it also is odd that other clients 
don't have this issue. Are you looking at messages with exactly the same 
alternative address but different clients?

> Is it possible to use mailmate with Gmail, to send as a different 
> email
> address, similar to what I do with other mail clients? What are the 
> steps
> to do this?

I can't answer this directly, as I have no GMail account set up for 
sending from non-GMail addresses. I can say that unless MM is sending 
via GMail differently than it does for other SMTP servers (which would 
be a surprise) it is doing the best that it can and the problem is with 
GMail's quirks or an external issue like SPF.

-- 
Bill Cole
bill at scconsult.com or billcole at apache.org
(AKA @grumpybozo and many *@billmail.scconsult.com addresses)
Not Currently Available For Hire