This question already has an answer here:

We are having a big spam problem and we don't know how to resolve it. We have one spammer that send us mail daily. All these emails are from different themes, using different email addresses that are only used one time, and the domains are used only one time. So we don't have any way to stop it. The only pattern is that the domain names are really young and are registered the same day the spam is send. They use .us and .me domains.

Any suggestion to resolve this problem?

marked as duplicate by ewwhite, Ward, Cristian Ciupitu, sysadmin1138 Jul 30 '14 at 19:48

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

  • 1
    This would depend on the kind of mail server you are using. An alternative approach would be to use a service provider to host your mail instead of doing it yourself, as those have usually a lot of experience with this kind of problem. – Sven Jul 29 '14 at 9:27
  • How about keywords in the body of the mail? Another option is to blacklist every inseureserver you get spam from, along time it should substantially reduce the masses. – EliadTech Jul 29 '14 at 9:36
  • Details... what mail server solution are you using? – ewwhite Jul 29 '14 at 12:25

There's a project called the Anti Spam SMTP Proxy on SourceForge,
here: http://sourceforge.net/projects/assp/

You could build a server and put ASSP on it (Windows will probably be easiest)
and after a week or two of collecting spam and ham (non-spam) messages, you can begin to block spam.
A smart thing to do during the collection period is to send all of your past emails to a ham-collection address, which will whitelist and analyze the emails for words and recipients which should be trusted.

ASSP uses various techniques to score emails, so it can intelligently block the emails that you described in your post.

Not the answer you're looking for? Browse other questions tagged or ask your own question.