About the Email Dossier validation tool
The Email Dossier tool checks the validity of an email address by stepping through the process of sending email and showing you results along the way. It stops short of actually sending any email but can point out errors and give you insight into where things have gone wrong.
NOTE
No validation tool can tell you with certainty that an email address is good. It can only tell you when an address definitely won’t work. Email Dossier helps you discover a variety of problems that might otherwise be invisible to you, and, if it finds none, you can have some confidence in the email address.
Contents
Entering an address
To get started, simply enter the email address you want to check. The tool accepts a wide range of syntax.
The tool will then check the syntax of the address, look up the mail servers for the address’ domain, and try contacting those servers as if it were going to send mail to the address. The tool always stops short of sending anything.
Validation results
After testing the email address you entered, the tool gives a summary of results.
Confidence rating
The confidence rating gives a sense of how much confidence you can have in the email address’ validity. The number can range from 0 to 3.
A rating of 0 indicates no confidence—a bad address. The subsequent error message will give more detail about what’s wrong.
A rating greater than 0 indicates that the tool could find nothing wrong with the address, though the address could still be bad. Normally the rating will be 3 but could be less if a technical problem prevented doing all the tests.
Error
The error code and message give more detail on the problems encountered while checking the email address. If no problems were found, there will be no error message.
Canonical address
Email addresses can contain several special encodings and forms. If the tool finds that the syntax of the entered email address is correct, it will convert the syntax of the address to a consistent form and display it here. For example, the address:
user@crème-brûlée.example
would be normalized to its ASCII-compatible form:
<user@xn--crme-brle-13ar8s.example>
If the syntax of the entered email address isn’t correct, there will be no canonical form.
MX records
If the tool found MX records for the email address’s domain, it will display them in this section. MX records point to the mail servers (“Mail eXchanges”) for a domain.
For each server there will be a preference number (lower values mean the server is more preferred) and the domain name of the server. If the DNS returned IP addresses for the MX servers as well, the tool will display them.
SMTP session
If the tool is able to contact a mail server for the email address’ domain, it will display the conversation with the mail server in this section. (The Simple Mail Transport Protocol is a text-based protocol.) This transcript can help understand the server’s capabilities and why it rejected the given email address, if it did.
The lines highlighted in green and enclosed in square brackets are comments from the tool to show what it did or what it recognized.
Blue lines beginning with four-letter commands show what the tool sent to the mail server.
Black lines starting with numeric codes are responses from the mail server.
Be sure to check out our other free network tools at CentralOps.net and our Whois API at Hexillion.com.