Question: How can i make a script like verify-email.org ?
I told in the school, that this is not a problem. But now, I searched the web, and found nothing?

E.g. test123@hotmail.com

* I don't want only check if the domain exist of the E-Mail address. I want check, the whole E-Mail, if it exists on Hotmail.com?

Thanks.

Answer: 
You can't. You have to send an email and wait for an answer to verify that this address exists.
The only clear way to check an email address is valid is to send it an email. If it isn't valid you will get an undelivered response.