Preface

Simple Mail Transfer Protocol (SMTP) which is the standard for email transmissions across the Internet was designed in the good old days when nobody could even think of the possibility of e-mail being abused to send tons of unsolicited messages of dubious contents. Therefore it lacks mechanisms that could have prevented this abuse (spamming), or at least could have made it difficult. Attempts to introduce such mechanisms (such as SMTP-AUTH extension) are being made, but they are not in wide use yet and, probably, their introduction will not be enough to stop the e-mail abuse. Spamming is today’s grim reality and developers spend lots of time and efforts designing new protection measures against it. Mailfromd is one of such attempts.

The package is designed to work with any MTA supporting ‘Milter’ or ‘Pmilter’ protocol, such as ‘Sendmail’, ‘MeTA1’ or ‘Postfix’. It allows you to:

• Control whether messages come from trustworthy senders, using so called callout or Sender Address Verification (see SAV) mechanism.
• Prevent emails coming from forged addresses by use of SPF mechanism (see SPF Functions).
• Limit connection and/or sending rates (see Rate Limit).
• Use black-, white- and greylisting techniques.
• Invoke external programs or other mail filters.