Various countermeasures have been deployed to solve the problem of open mail relays – first SMTP-After-POP and then ESMTP and ASMTP in 1995. Furthermore, the constant change of fake addresses made it possible to avoid spam filters. By using external hardware, the spammers also saved their own resources and so could not be traced back. Since the servers did not have additional authentication mechanisms at the time, they accepted the spam mails without difficulty and fed them into the network. The term given to this practice is “mail spoofing”. Morally questionable advertisers and malicious criminals (above all, the notorious “spam king” Sanford Wallace with his Cyberpromo firm) used the open servers with stolen or invented e-mail addresses to distribute spam. However, the widespread use of such unprotected relays led to the proliferation of spam. What seems absurd in today’s environment was originally founded in good reason: system errors and server failures were more frequent, so open mail relays could maintain regular traffic even in emergency situations. mail servers that forward all e-mails regardless of the sender or recipient address. For this reason, open mail relays were the norm until about 1997, i.e. The need for this procedure is due to the inherent features of the original 1982 SMTP, which did not provide user authentication by default. SMTP AUTH prevents an SMTP server from being misused as an open mail relay and distributes spam within a network.

Apple mail smtp authentication