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 is a valid email address, via the Linux operating system.

get the mail host: host -t MX <email domain>
$ host -t MX
Here's the list of email servers that accept email for mail is handled by 5 mail is handled by 5 mail is handled by 5 mail is handled by 5
End of mail server list
Connect to the host on port 25: telnet <mail-host> 25
$ telnet 25 Trying Connected to Escape character is '^]'. 220 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 Hello []
Your email address
mail from: 250 OK
Email address to be tested
rcpt to:
This address doesn't seem to be valid
550 Requested action not taken: mailbox unavailable rcpt to:
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?