Mail Finder Fast 

Mail Finder is an elegant tool for finding email addresses on a specified domain.It is fast,reliable and easy to use.It can verify up to 120.000 emails per hour on a standart telephone line connection with a 56K modem.
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Advanced Maillist Verify 

AMV determines which of addresses in mailing list are dead. The program supports databases (ODBC SQL), TheBat, Eudora and Windows address books, Socks5 proxy protocol. Has open ActiveX/COM and CGI/ISAPI interfaces for developers.
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Contacts Verifier 

Contacts Verifier is the Microsoft Outlook add-in designed to monitor the validity of email addresses. It is able to check your contacts throughout in a few minutes and notify you of contacts that contain invalid email addresses.
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