This article contains an analysis and solution for blocking of international SPAM botnets with on postfix mail servers by using a postfwd plugin which analyses the sasl connects by country.
One of the most important and hardest tasks for every company that provides mail services is staying out of the mail blacklists. If a mail domain appears in one of the mail domain blacklists, other mail servers will stop accepting and relaying its e-mails. This will practically ban the domain from the majority of mail providers and prohibits that the provider’s customers can send e-mails. Tere is only one thing that a mail provider can do afterwards: ask the blacklist providers for removal from the list or change the IP addresses and domain names of its mail servers.
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