eVerify Description:

eVerify is designed for administrators, webmasters, programmers as well as for those users who have their own mailing lists and would like to keep them current.
eVerify is a program that can be used to verify the validity of e-mail addresses in your mailing lists. The program works on the same algorithm as ISP mail servers do. Mail servers addresses for a specified e-mail address are extracted from DNS. The program tries to connect with found SMTP-servers and simulates the sending of message. It does not actually send the message  eVerify disconnects as soon as the mail server informs the program whether the email address exists or not. eVerify can find about 90% of dead addresses  some mail systems receive all messages and only then see their addresses and if the address is dead send the message back with remark about it. Works with Socks5 proxy (to use in a LAN environment).
eVerify saves you valuable bandwidth and time.