Redirect Script on index.php Not Working 100%

[sunshinelock]

I don't know if I did this incorrectly from the start, but this is my situation:

 

I have multiple domains pointing to the same server space.  I have a php script in the index.php of the root that figures what domain was typed, then serves up the proper page.

 

For instance, here is a sample of my script, edited to not give away too much information:

 

<?php
//$host = $GLOBALS['HTTP_HOST'];
$host = $_SERVER['HTTP_HOST'];

$site1 = "site1";
$site2 = "site2";
$site3 = "site3";
$site4 = "site4";

//if site1
if(stristr($host, $site1)){
header('Location: http://www.site1.com/site-one-index.php');
}

//if site2
elseif(stristr($host, $site2)){
header('Location: http://www.site2.com/site2/index.php');
}

//if site3
elseif(stristr($host, $site3)){
header('Location: http://www.site3.com/site-3/');
}

//if site4
elseif(stristr($host, $site4)){
header('Location: http://www.site4.com/site4/file/index.php');
}

else {
include "script/config.php";
include "script/detect.php";

if ($page_name=='') {
include $browser_t.'/index.php';
}
elseif ($page_name=='index.php') {
include $browser_t.'/index.php';
}
else
{
include 'errors/404.php';
}
};
?>

Now, this works great if somebody types in the address properly.  Even if somebody types in the wrong address, it will direct somebody to a nice 404 page.

 

The problem is if somebody types in a page that doesn't exist, and ends it with "/".

 

For instance, www.SITE.com, works like it should.

www.SITE.com/page.php works like it should.

www.SITE.com/folder works like it should (serving up an error page).

www.SITE.com/folder/ works like it should if I have an actual index.php file in that file (serving up the index.php page)

www.SITE.com/nonexistantfolder/ does not work properly.  It serves up a fake index.php file, not directing to the 404 page.

www.SITE.com/nonexistantfolder/index.php does not work properly. It serves up a fake index.php file even though it's not physically on my server.

Google thinks my site is hacked because apparently there are hundreds of SITE.com/nonexistantfolder/ pages serving the exact same index.php file, when instead there should be a redirect to a 404 page.

 

I've been thinking for months how to fix this. I cannot wrap my head around it.  I need to somehow take every "/" or "/index.php" and check my actual server space for a physical copy of an index.php file and return that, or send them to a 404.php page.

 

I just can't figure this one out.

[benanamen]

If you have multiple sites you need to set up Apache (or whatever server you use) to direct to the proper site. You are going about this completely wrong.