RE: [PHP] obtain IP from other site ( or domain name)

> I have exchange link business program with other sites, > basically I give a hyper link to come to our store to them > and when user click on the link on their site to come to us, > they will genrate income from it too. > The question is that how do I know that when a user click on > the link to come to my site that a user come from the link > from their site , or from their IP or something. So that I > can tell where a user come from. > Is this something to do with http header? You can look at $HTTP_REFERER, but its not reliable. Better to tell them to use linking code that specifically has a parameter in it that your receiving PHP script can pick up. Instead of http://www.yoursite.com/ give them that with ?linkid=X so you could track clickthroughs. Jason