This Free Email Verifier actually connects to the mail server and checks whether the mailbox exists or not.
Here are two images showing the use of email verification tool ...type or copy & paste the address into the box and click verify...twice.
This log appears bottom-left of page.
To use the Free Email Verifier...click on..... http://verify-email.org/
NOTE: You have to be logged on to the Symposium to be able to click on the link and go to the site..... if not logged in then copy and paste the url into your browser.