Server Variables and IP addresses??

I have been looking into this server Variable stuff, like it so far, just need to know how, when someone visits the page, to get unique details from them (like there ip address) but somthing that will always be the same when they visit the site, even after logging off and on. Also, how is an ip made up? what do the numbers mean.

Thank you againIf you want to be able to identify users each time they come to your site, you either need to give them a cookie with a unique value, or have them identify themselves by logging into your site. (A cookie is a small file with values which you send to the browser and ask the browser to send back to you when they re-visit your site.)

As you noted, users don't consistently have the same IP address. Basically, IP addresses are sold off to ISPs and businesses and are handed out to users as they connect to the network, making sure that no two users have the same IP at the same time. The number is just a unique value allowing you to communicate with the particular computer which has the address assigned. Each IP address is a 32-bit value, which we write as 4 8-bit values separated by periods to make them easier to read (192.168.115.30).

Hope this helps,
-Scott