MailInput

This email verification tool actually connects to the mail server and checks whether the mailbox exists or not. Email Checker is a simple tool for verifying an email address. It's free and quite easy to use. Just enter the email address and hit the verify button. Then it tells you whether the email address is real or not. It extracts the MX records from the email address and connects to the mail server (over SMTP and also simulates sending a message) to make sure the mailbox really exists for that user/address.