check if email are valid and exists

Question

I am working on a web app that requires me to check if the users email are valid and exists. (I do the regex check) The question is what is best practice of verifying that an email exists?

Here are some options that I have though about:

1. send an email to the user and make them confirm the email address
2. do a VRFY SMTP - is this still used? should i bother looking into it?
3. any other good idea?

Answer 1

sending a verification email to the user verifies that the email is valid and that the user is the owner of the account