How to check if an email address really exists

In this article, you’ll learn how to use the command line to verify whether a specific email address exists or not, without sending an email. You don’t have to pay for any software or online services and you don’t have to send out test emails. You can do it all for free through the command line, without any limits on how many times you can do it!

When you send an email to user@domain.com, the sending mail server will look up the MX record in DNS for ‘domain.com’ and if one or more MX records are found, the sending mail server will try to deliver the email to the mail server specified in the domain.com MX record.

Let’s try to verify if the address someuser@gmail.com exists or not. First, we need to find the MX records associated with the recipient’s domain, in our case that is gmail.com. We will use a DNS lookup utility called dig which is installed on most Linux systems

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