How to remove a bunch of requests to SMTP?

Question

postfix

Can you please tell me what is happening on the server?
When I closed access from any ip, I myself could not send requests, but here they are constantly coming, how to fix this?

Answer 1

It seems that you have a relay open, that is, through your server, absolutely anyone can send a letter from any address to any other.
On a good note, only letters to your domain, or connections with authorization, should be accepted from the outside. Only letters from your domain should go outside, and preferably with a DKIM signature.
Check the server here:https://check.smtp.bz/