See the //email/test To: ("TestReceiver") Full Documentation for complete information.

How to run it

Type in the email address of someone that you send email to.

Leave the Output Level set to "Detail".

Click the Run Test button.

What it does

When you click Run Test, //email/test To: ("TestReceiver") performs all the steps that Internet email systems go through to send email. It records every command and byte of data it sends and every answer and byte of data that the other email system sends. TestReceiver never actually sends an email, it just gets as close as possible, learning as much about the remote system as it can.

Because CheckTLS focuses on security, TestReceiver tries to establish a secure (TLS) connection with the recipient's system. Along with recording everything, it looks at the security of the recipient's system for things like: certificate contents and signers, encryption algorithms, key lengths, hostname mis-matches, incorrect wild-card usage, weak cyphers, etc.

What it shows

Confidence Factor

For all Output Levels, the first thing TestReceiver shows is our unique Confidence Factor. This is our "grade" (zero to 100) for the recipient's email system. It takes into account all the security information gathered while it was connected with the recipient's email system. For domains with multiple email servers (MX hosts), it weighs how many there are and their priority. It computes a single number for the given email address that is our opinion on how securly it will receive email.

We suggest that a Confidence Factor of 90 or above indicates that the email address is "secure".

MX Matrix

The next level of output is the MX Matrix. TestReceiver groups the steps of sending an email into 8 stages. The MX Matrix shows, for each MX host, how long each stage took and whether it was successful or not. Use the MX Matrix to look deeper into an email system, both down the matrix (by MX Host) and across the matrix (by stage), to show where strengths and weaknesses are in the system.

See the TestReceiver Full Documentation for more information about the MX Matrix stages.


The next levels of output are all Detail. Detail is the log of TestReceiver's interaction with the recipient's email system. Depending on the Output Level chosen it also shows what is inside the remote system's SSL Certificates and the details of the SSL connection established with the remote system.

See the TestReceiver Full Documentation for more information about what the Detail levels show.

FULL Version fields
Input Fields
TestReceiver parameter entry
  1. - + (less/more output)
FULL Version
  1.   (invalidates the Confidence Factor)
  2.   (see rfc-2818 section 3.1 paragraph 4)
  3. (seconds)
  4.   (not recommended)

See what else you can test: How To.

Test Results

Test results will show here when a test is run.