How to block referrer spam in IIS / Asp.Net and Apache

What is Referrer Spam

Referrer spam are spam referrals generated by a bot who visit your site with the intent of 

• building links for their domain to improve their search rankings. Sites who publish their access logs with referrer details would have provided a free link to the spam url.
• lure curious webmasters into visiting their sites to gain some traffic or potentially infect their computer.

How does it affect your website

At first it doesn't seem it could have a lot of negative effect on your website. However, all these requests do utilize your bandwidth, potentially affecting genuine users. Also if you are monitoring your website usage using Analytic tools, your statistics get annoyingly skewed, giving you incorrect data.

Blocking Referrer Spam in SquareSpace

You need to add redirect rules for the spamming website, similar to the htaccess solution in Apache section down below. But there is no .htaccess file in squarespace. However there is something similar in the backend of your Squarespace site. Click on the wrench icon, then go to advanced. You'll be able to add redirects there. Check the Apache section below for .htaccess file code to get a sample idea. Don't hide this traffic in Google Analytics. That is just turning a blind eye to the issue.

Blocking Referrer Spam in IIS

Open your web.config file and add the following rule under system.webServer (If it does not exist create it under configuration)

  <system.webServer>
    <rewrite>
      <rules>
        <rule name="Block darodar" patternSyntax="Wildcard" stopProcessing="true">
          <match url="*" />
          <conditions>
            <add input="{HTTP_REFERER}" pattern="*.darodar.com" />
          </conditions>
          <action type="AbortRequest" />
        </rule>
        <rule name="Block seoanalyses" patternSyntax="Wildcard" stopProcessing="true">
          <match url="*" />
          <conditions>
            <add input="{HTTP_REFERER}" pattern="*.seoanalyses.com" />
          </conditions>
          <action type="AbortRequest" />
        </rule>
        <rule name="Block internetsupervision" patternSyntax="Wildcard" stopProcessing="true">
          <match url="*" />
          <conditions>
            <add input="{HTTP_REFERER}" pattern="*.internetsupervision.com" />
          </conditions>
          <action type="AbortRequest" />
        </rule>
        <rule name="Block ilovevitaly" patternSyntax="Wildcard" stopProcessing="true">
          <match url="*" />
          <conditions>
            <add input="{HTTP_REFERER}" pattern="*.ilovevitaly.co" />
          </conditions>
          <action type="AbortRequest" />
        </rule>
        <rule name="Block musicprojectfoundation" patternSyntax="Wildcard" stopProcessing="true">
          <match url="*" />
          <conditions>
            <add input="{HTTP_REFERER}" pattern="*.musicprojectfoundation.com" />
          </conditions>
          <action type="AbortRequest" />
        </rule>
        <rule name="Block myprintscreen" patternSyntax="Wildcard" stopProcessing="true">
          <match url="*" />
          <conditions>
            <add input="{HTTP_REFERER}" pattern="*.myprintscreen.com" />
          </conditions>
          <action type="AbortRequest" />
        </rule>
        <rule name="B