07-09-10 | Blog Post
My past few posts have been largely about email systems and spam filters which for the most part can provide you with fast and reliable message delivery system. However there are still many things that can impede the healthy operation of your mail server.
Nearly all abusive email messages now come from a forged or fake address which can be done easily by hackers in order to misdirect the receiving mail server. This misdirection allows them to continue to send out spam, virus, and phishing scheme laden email without the fear of being blocked by Anti-spam services. An attack of this kind on your server can slow your email system to a stop since most reputable mail systems will block a server that even remotely resembles a spam sender.
One of the most effective ways of preventing a spammer from spoofing your address and potentially dirtying your domain name is to create an SPF or Sender Policy Framework record in your DNS zone. SPF records prevent sender address forgery by protecting the envelope sender address, allowing the domain administrator to specify which mail server are allowed to send mail from their domain. This anti-spam method however requires that you have a properly formatted SPF record and the receiving server has the ability to check if the message complies with this record. SPF is an open standard and is constantly updated by the vast community of its supporters.
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