How to check if an email address exists without sending an email?

Question

I have come across this PHP code to check email address using SMTP without sending an email.

Has anyone tried anything similar or does it work for you? Can you tell

Answer 1

Some issues:

1. I'm sure some SMTP servers will let you know immediately if an address you give them does not exist, but some won't as a privacy measure. They'll just accept whatever addresses you give them and silently ignore the ones that don't exist.
2. As the article says, if you do this too often with some servers, they will blacklist you.
3. For some SMTP servers (like gmail), you need to use SSL in order to do anything. This is only true when using gmail's SMTP server to send email.