Online Demo : http://emailchecker.giveawaysnetworks.net/
Asp.Net Super eMail Checker is a simple & easy-use web application that allows you to verify email addresses without storing anything in any databases. 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.
**Some mail servers do not cooperate the verification process with the MX records, in such cases, the result of this email verification tool may not be as accurate as expected (1% error margin).
Note: Source Code Is Included.