Question

I have a software package placed in the root directory of my website. I’d like all visitors which come from other websites to see the homepage first, before they download. How can I do that without using a script?

Answer 1

Apache’s mod_rewrite can do this. It can test ‘HTTP_REFERER’ variable and create a redirect.

Example from http://httpd.apache.org/docs/2.0/misc/rewriteguide.html

Description:

Assume we have under
http://www.quux-corp.de/~quux/ some
pages with inlined GIF graphics. These
graphics are nice, so others directly
incorporate them via hyperlinks to
their pages. We don’t like this
practice because it adds useless
traffic to our server. Solution:

While we cannot 100% protect the
images from inclusion, we can at least
restrict the cases where the browser
sends a HTTP Referer header.

RewriteCond %{HTTP_REFERER} !^$
RewriteCond %{HTTP_REFERER} !^http://www.quux-corp.de/~quux/.*$ [NC]
RewriteRule .*\.gif$        -                                    [F]

RewriteCond %{HTTP_REFERER}         !^$
RewriteCond %{HTTP_REFERER}         !.*/foo-with-gif\.html$
RewriteRule ^inlined-in-foo\.gif$   -                        [F]

Other variant http://articles.sitepoint.com/print/apache-mod_rewrite-examples

RewriteCond %{HTTP_REFERER} !^$  
RewriteCond %{HTTP_REFERER} !^http://(www\.)?example\.com/.*$ [NC]  
RewriteRule \.(gif|jpg|png)$ http://www.example.com/hotlinked.gif [R=301,L]

First line checks if referer is empty. second – if it is not your domain.
Third will redirect “bad queries” to “hotlinked.gif”