Email Verification

This is a method that can be used to verify if an email address is active via the unix console. Comments are indented. It does not always work. This example checks to see if test52673@hotmail.com is a valid email address, via the Linux operating system.

    
get the mail host: host -t MX <email domain>
$ host -t MX hotmail.com
Here's the list of email servers that accept email for hotmail.com
hotmail.com mail is handled by 5 mx2.hotmail.com. hotmail.com mail is handled by 5 mx3.hotmail.com. hotmail.com mail is handled by 5 mx4.hotmail.com. hotmail.com mail is handled by 5 mx1.hotmail.com.
End of mail server list
$
Connect to the host on port 25: telnet <mail-host> 25
$ telnet mx1.hotmail.com 25 Trying 65.54.252.99... Connected to mx1.hotmail.com. Escape character is '^]'. 220 mc5-f30.law1.hotmail.com Microsoft ESMTP MAIL Service, Version: 5.0.2195.5600 ready at Mon, 13 Jan 2003 20:50:59 -0800
Your name/nickname
helo BarkerJr 250 mc5-f30.law1.hotmail.com Hello [127.0.0.1]
Your email address
mail from: bark_jr@hotmail.com 250 bark_jr@hotmail.com....Sender OK
Email address to be tested
rcpt to: test52673@hotmail.com
This address doesn't seem to be valid
550 Requested action not taken: mailbox unavailable rcpt to: bark_jr@hotmail.com
This one is valid
250 Requested mail action okay, completed
By typing "quit," no email is sent
quit 221 Service closing transmission channel Connection closed by foreign host.

Some mail servers will accept an email and bounce it back later. The only sure way to know if an email address is active is by sending email to it. But, sending email to a spammer, directly, is considered baiting, and you can't really call further emails from him or her "unsolicited," can you?