In you're httpd.conf do the following:
Search for this in you're httpd.conf:
#LoadModule proxy_module modules/mod_proxy.so
by default it is shown as shown above. change it into:
LoadModule proxy_module modules/mod_proxy.so
Then in you're VirtualHost block:
<VirtualHost *:80>
ServerAdmin
webmaster@dummy-host.example.com
DocumentRoot c:/webserver/www.domain.com
ServerName
www.domain.com
ErrorLog logs/dummy-host.example.com-error_log
CustomLog logs/dummy-host.example.com-access_log
ProxyBlock puntjuhdomain.com
</VirtualHost>
Make it look like above.
this will block all proxy's with puntjuhdomain.com .. if you wanna block more domains just add a space and type the next domain. If you wanna ban all proxy's just do this:
ProxyBlock *
good luck