Email Validator checks deliverability of email addresses. It does so by first performing a DNS query on the domain name of each email address in order to determine the address of the mail server servicing that domain. Once the mail server is found, a connection is made in the same way as your ISP's mail server would make a connection. Email validator will first attempt to use the SMTP VRFY command to determine deliverability. If the VRFY command is enabled, the mail server will report whether the email address being tested is in fact deliverable, Email Validator will then close the connection and report the result.
In many cases the VRFY command is disabled on SMTP servers. If this is the case for any given mail server, Email Validator will then attempt to simulate the delivery of an email message. During this process, the mail server will report whether or not it can accept a message for the email address being tested. Once this is reported, Email Validator will close the connection and report the result. NO EMAIL IS ACTUALLY SENT. Email Validator never gets to that point, so the owner of the email address will not receive any message as a result.
Once a list of email addresses has been tested, the user may export all addresses along with test results or simply export all deliverable or non-deliverable addresses in order to clean an existing list or build a new one containing only deliverable addresses. The result for anyone who runs a mailing list, i.e. ezine and newsletter publishers, businesses, political parties, non-profit organizations, etc. can save time and money by sending mail only to deliverable addresses and not have to clean delivery failure notices out of their inboxes.