[courier-users] SPAM over SMTP

[Alexey I. <lef...@ma...>]

Hi,
 
Recently I have started to receive SPAM from mail.governorsperic.xyz
The porblem is, that that MTA allows to smbd may be to the owner
to send emails like from (in my case) my domain, which won’t work otherwise
over IMAP. I have banned that domain in my local DNS, but it didn’t help.
 
As commonly used by companies, mostly start-ups the domain name
in the email and responsible MTA agent are not matching like in my case.
 
One of the best examples is outlook.office365.com, which work for many
domains not related to the given one.
 
May be I was not clear…
here an example:
 
SMTP = smtp.office365.com
EMAIL =   na...@my...
 
Obviously I don’t have control over smtp.office365.com
But I don’t wish any one send me an email with address like:
na...@my...
 
because, that user is (may be) not existent and surely not authenticated.
 
What is the best practice to do in such a case?
Ban mail.governorsperic.xyz from sending me mails? But they can create
another one like that. What if it will be smtp.office365.com ?
I cannot ban it obviously w/o loosing tons of emails.
 
I wish that no one can send me emails from outside with my own domain,
what ever server it might be!
 
If they will be using other domain (not mine) I don’t have any chances
to prove, whether it is valid mail address (domain) or not. At least it would be less confusing.
 
P.S. I know, that field FROM — can contain anything, not even related to the origin domain.
 
Thx
 
 
 
 
 
--
Alex