I have a query that gets 5 random values out of a table according to a query. i.e.

SELECT * FROM links WHERE url contra = FALSE ORDER BY rand() LIMIT 0,5

This is fairly simplified but you get...

Surely on a shared serverm that would just give you the name of the shared server, not the domain name that is calling you.

I have some code that is called from with other files, using readfile so there is no referer etc.

To authenticate that the request is where it should be from, the php is passed a calling url as...