Diagnosing email faults

Check SMTP runs a series of diagnostic tests on an SMTP server. These tests will reveal any errors in your DNS or SMTP server configuration. Such as missing, inaccurate or inappropriate MX and PTR (Reverse DNS) records or if the server is an Open Gateway. The test requires an email address for the domain so that it may check the mailbox status, supplying a valid email address will also ensure that emails cannot be sent from your server by an unauthorized 3rd party. The email address is recorded, to prevent abuse by spammers, but the address information is not available to anyone but the system itself. Check SMTP does not send any messages during the test.

You may return to a test report at any time using the URL provided once the test has completed, we recommend that if Check SMTP finds your server to be an Open Gateway that you do not link to the report from any public forum or on a media which a search engine can index.
Servers which have passed the test are listed in our Secure Server list.

Check SMTP performs the following tests:

  • Validates your DNS MX records
  • Validates your PTR records and checks for suspect entries
  • Confirms your SMTP server is not on the most popular a black/block list
  • Confirms your server accepts connections
  • Tests your SMTP servers gateway status
  • Attempts to send a message by impersonating your email address
  • Verifies the recipient mailbox is ready to receive email

Again, please note, no emails are sent during the test. Check SMTP attempts to impersonate the email address you have provided but only requests that the server allows you to send an email using this address. Once Check SMTP has received an answer from your server it disconnects and continues with the next test.