NoSpamToday! for Servers - Directory Harvesting Attacks

Directory Harvesting Attack Protection

Directory harvest attacks are used by spammers to find valid mail addresses in your domain. The attacker, for example, goes through a list of common first names and combines them with your domain name to issue SMTP RCPT TO commands, like this:

If a your mail server accepts this address, the spammer takes this as an indication that this address is valid.

NoSpamToday! counts the number of failed RCPT TO commands in a SMTP session. As soon as this counter exceeds a configurable limit, the remote host is disconnected. This counter is reset whenever a RCPT TO command is successful. You can set the limit on this page of the SMTP proxy port setup wizard. The default setting is 10.

Learn More ...

• Read more about NoSpamToday!'s Mail Flooding Protection and Traffic Limiting.
• Read more about NoSpamToday!'s Open Relay Protection.
• Read more about NoSpamToday!'s Core Features and Benefits.

You Are In Good Company...

Many leading companies and organizations have already chosen NoSpamToday.


"I just wanted to say THANK YOU for your awesome product NoSpamToday!. Before I installed your product I was getting approximately 400 SPAM messages a day. After installing your product, I haven't received a single one. I am very impressed, your product is very easy to use and works great even in my overcomplicated home network. I just can't praise this product enough. It's such a time saver not to have to worry about SPAM anymore. I have not noticed any false positives and the SPAM catch rate is amazing." Joe Church

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