IP Address Software ...???

[BuyDell]

   Is there a application or software program that I can use to identify a persons IP address...? I host a website that gives a 3 day trial and I want a way to know if they've been there on the site previously....

   Thanks for any help.

[kpac]

Here's an example: http://stackoverflow.com/questions/4821431/check-if-same-user-visited-web-site-how

[Rob Pomeroy]

Note: An IP address is not sufficient to uniquely a person.  Proxies, corporate networks etc. cloud this issue.

[Jason_Martin]

For you I have searched a website in google which is wikihow.com/Trace-an-IP-Address. But keep in mind that using proxy websites IP can be hidden or changed and their are many softwares available in the market to hide IP addresses.