Spam from the company's e-mail. What to do?

Question

Fight against spam

Angry letters come to a company I know at the postal address - “Exclude us from the mailing list.” Although she does not conduct any mailing lists. Mail is used purely for communication with clients (Familiar - Private Entrepreneur).
What can you advise her?

Answer 1

SPF, DKIM

Answer 2

1. Change password to mail
2. Send angry messages to spam

Answer 3

Ask to send one of these letters with all the headers, see who really sends it, write to the host. Well, screw SPF with the correct PTR and other joys of life.

Answer 4

There was a similar situation.
I solved it like this:
1. I found out from which service the letters come (from the letter headers) - for example
Received: from user37 by exampleservice.com with local (Exim 4.74)
(envelope-from <[email protected]>)
id 1Rgskc-0008Hw- GD
for [email protected]; Sat, 31 Dec 2011 08:49:06 +0200
2. Wrote a letter of complaint against the user for SPAM (the address was taken from the service website). If necessary, sent email headers to prove the existence of emails
3. If no one did anything about the user, then with the help of 2ip.ru he found out who had the company's servers and wrote to the hoster.
In my case, the site owner of the mail service did not react in any way (since it was the service of one company), but the hoster (in my case, DC Volya) turned off the server, since I was not the only one who received SPAM

Answer 5

The scheme is simple. I take someone else's soap (knowing the password from him), I register, for example, in a webassist . I send spam from this email through webassist, even if this person has already changed the password from the mailbox :) And damage the reputation of the owner of the email (company)

Answer 6

We need to deal with specific cases. Often there are unfortunate spammers who create mailing lists where anyone can write and where the address of the list is substituted as the address for answers. And then in this spontaneous list begins a skirmish like "get me out of here" that all the other victims get.