If the server is an esmtp server, you can issue commands link VRFY. There is also another command that you can use. I think it's EXPN or something like that. At any rate, you should be on to a good start. The VRFY command is used to verify that an email address is configured for delivery at said host.

In reply to Re: SMTP Validation by Anonymous Monk
in thread SMTP Validation by Anonymous Monk

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