Is there a way to univocally recognize users? (PHP)

[Reg]

I'm making a visit counter for my dad an he wants it to not record his own visits. I first thought about IP, but we have a router that gets a different IP every time we turn it on, so that wouldn't work. I also searched about the MAC address, but it looks like php can't access it. Is there any other way to recognize a connection?

Edit: posted in wrong section, sorry

[M-D]

Why not look at something like Google Analytics?
They're pretty good at recognizing returning visitors.

Otherwise you could use a combination of the users IP address and the cookie.

[Reg]

what cookie?

[Kirth]

Feed your father's PC a cookie.

setcookie("dad", "quite likely");

Incidentally you might just want to go with a boolean value for said cookie.

Then in your tracking script:

if(!isset($_COOKIE['dad']))
{
    #  Code here
    //  Turtles are AWESOME.
}

[mdakin]

Ew cookies.

[M-D]

[QUOTE=Reg;21349563]what cookie?[/QUOTE]

I meant "a cookie".

So you set your own cookie and then later see check it exists.