Hi, I saw that I had many such attacks...
Out: 220 MyServer ESMTP In: EHLO Oi9oRGhc Out: 250-MyServer Out: 250-PIPELINING Out: 250-SIZE 5000000 Out: 250-ETRN Out: 250-ENHANCEDSTATUSCODES Out: 250-8BITMIME Out: 250-DSN Out: 250 SMTPUTF8 In: AUTH LOGIN Out: 503 5.5.1 Error: authentication not enabled Session aborted, reason: lost connection OK, attacker tries to authenticate and receives an error. I see that almost all attacks do not have a valid FQDN, so I have set the "reject_non_fqdn_helo_hostname" directive in "smtpd_helo_restrictions" directive, which I see is in a previous phase, to reject it beforehand. However, it has no effect. The attacks continue to occur in the same way, and are rejected at the same point. Can you explain to me, why this happens? Best Regards,
