This question is not language-aware.
I wanna know how can I recognize a returning user on my website (Java, PHP, Coldfusion...) if he's using a dynamic IP.
Why? A lot of users of my web application use iPhone (with 3G networking) for accessing. IP changes each time, so I always see them as "new" users.
I know it's unlikely to track MAC address in web pages but.... what solutions are there for such a common problem?
Maybe a suitable iPhone app? ;-)
It's not quite possible to find original requesting machine's MAC address. You should use Cookies to track users.
You can find more info about MAC Addresses here.
A Media Access Control address (MAC address) is a unique identifier assigned to network interfaces for communications on the physical network segment. MAC addresses are used for numerous network technologies and most IEEE 802 network technologies, including Ethernet. Logically, MAC addresses are used in the Media Access Control protocol sub-layer of the OSI reference model.