What Is Unique Identity Of An Internet Connected Device Ip / Mac?

I am making a script that show popup only one time , then it will never show again on that device.. How is it possible to do this? I have already tried by using cookies, but these

Solution 1:

The only way is a cookie. There's nothing 100% uniquely identifiable about a machine that you have access to in an HTTP request. Yes, cookies may be deleted by the user. This is deliberate, live with it.

Solution 2:

The 2 options that are most obvious are either Cookies or a flag on an Account (if your users are authenticated).

Even though you've mentioned that cookies can be deleted, it's still a reliable form of saying "I have done something for this client before". If the user deletes the cookies then there's a high chance they know what they're doing, and should be expecting to have to repeat tasks (such as logging into other websites too).

If your users are authenticated (namely: they have to login to your site/service), then you can easily store a flag saying that the user has already been shown the notification.

That way is of course more reliable, but relies on authentication. Long story short: You need to take what you can get, and cookies are your best bet to have some form of unique device ID.

Regarding your other question: Nothing is unique in reality. MAC Addresses (which you wouldn't have access to anyway) can be spoofed, and IPs can be shared.

Solution 3:

Neither. Millions of Internet devices have 192.168.0.2 as their IP. So that's not unique. And MAC addresses aren't Internet things at all, they're Ethernet things.

If you explain your outer problem in more detail, there's probably a solution. But it sounds strangely bogus from what you've said already. The same person on two different devices should get the popup twice? But with two people on the same machine, the first person should get it only? It's hard to imagine a use case where you should go out of your way to ensure that.