Last weekend I received a notification from one of our web properties that it had experienced over 5000 errors in the past hour. I looked at the error log and noticed that the site was being hammered by a single IP address. I wanted to block the IP address until I could understand what was happening.

There is s security setting that can be set in the web.config as shown below:

      <ipSecurity allowUnlisted="true">
        <clear />
        <add ipAddress="" allowed="false" />