See the //email/testFrom:Full Documentation for more information.

How to run it

Start //email/testFrom: ("TestSender") by sending us an email.

See below for how and where to send the email.

Before using //email/testFrom: you may want to list in your list of allowed domains (whitelist us) so the report //email/testFrom: returns to you is not sent to your spam folder.

We cannot respond to Challenge-response email filters (e.g. SpamArrest, Support Sentry SpamBlock, iPermitMail) so you MUST manually allow mail from

This passcode only works once. You can refresh this page to receive another one.

Corporate Subscribers also have this option:

Save to file
Save the test result in a file our our website instead of sending it back to the sending email address. Use Get TS Results to view. Results are kept for one week.
Select Extra Items to Show What it does

When you send an email to the special address listed below with your unique passcode, //email/testFrom: performs all the steps that Internet email systems go through to receive email. It records every command and byte of data that your system sends and every answer and byte of data that our system replies back. //email/testFrom: does actually receive your email, and it learns as much about your system as it can in the process.

Because CheckTLS focuses on security, //email/testFrom: tries to establish a secure (TLS) connection with your system. Along with recording everything, it looks at the security of the your system for things like: certificate contents and signers, encryption algorithms, key lengths, hostname mis-matches, weak cyphers, etc.

What it shows

//email/testFrom: replies to your email with its results.

The reply email looks like one of these:

From: CheckTLS Test Sender TLS <>

SUCCESSFUL //email/testFrom:

Your email was sent securely using TLS.

From: CheckTLS Test Sender TLS <>
Subject: FAILED

FAILED //email/testFrom:

Your email was sent, however it was NOT SENT SECURELY using TLS.

Extra Items Shown
Input Fields
TestSender parameter entry

This //email/TestFrom: test ("TestSender") requires you to send us an email after you tell us to listen for it.
Open Instructions/Info above for more information.

Select Extra Items to Show

More information will show here when a Listener is Started.