Finding out which hosts receive email for a domain name (MX Records)

You can use InternetPeriscope to find out which hosts receive email for a domain. To do this, you look up the Mail Exchange (MX) record of the domain, using DNS.

To bring up the DNS Tool, click on the "Tools" menu, move your mouse over the "DNS" menu item, and click on "DNS Query...", as shown in the figure.
Tools menu

In this example, we will find out which hosts receive email for the domain In the figure below, the user has entered the name "" into the "Query String" text field, and has clicked on the "Mail Exchange (MX) Records" radio button. She then clicks on the "Send Query" button.
Send Query

Note that she entered "" into the "query string" text box, and not "". This is because she is interested in knowing which hosts receive email for If she wanted to know which hosts receive email for, then she would enter "" into the "query string" text box.

After a few moments, the DNS Query results dialog appears.
DNS results dialog

This dialog tells us the following:

  • If you were to send mail to, the email would go to the host It would go to this host because it has the lowest numbered preference, 10.
  • If was unreachable (perhaps it crashed, or is too busy to handle new email), then the email would be temporary stored on This is because has the next highest preference number, 20.
  • If and were unreachable, the mail would be temporarily stored on (preference 30), (preference 40), (preference 60), or (preference 70).
  • If you send email to someone at, it is very likely that your email will reach its destination. has 6 servers that can back up it's email in case one of its servers has a problem.

You can find out what kind of mail servers is using by using the Fingerprint Mailserver tool.