blocking semalt referrers with htaccess rules

Question

I have implemented the following code to htaccess but are still seeing referrers from semalt, such as:

74.semalt.com
89.semalt.com

The code

Answer 1

Your code looks good, syntax checks out ok! I used these mod_rewrite methods:

RewriteCond %{HTTP_REFERER} ^http(s)?://(www\.)?semalt\.com.*$ [NC]
RewriteCond %{HTTP_REFERER} ^http(s)?://(.*\.)?semalt\.*$ [NC,OR]
RewriteCond %{HTTP_REFERER} ^https?://([^.]+\.)*semalt\.com\ [NC,OR]

or with the .htaccess module mod_setenvif

SetEnvIfNoCase Referer semalt.com spambot=yes
SetEnvIfNoCase REMOTE_ADDR "217\.23\.11\.15" spambot=yes
SetEnvIfNoCase REMOTE_ADDR "217\.23\.7\.144" spambot=yes

Order allow,deny
Allow from all
Deny from env=spambot

I even created an Apache, Nginx & Varnish blacklist plus Google Analytics segment to prevent referrer spam traffic, you can find it here:

https://github.com/Stevie-Ray/referrer-spam-blocker/