Overview
The following explains how to read email headers to help troubleshoot mail issues.
What do email headers tell me?
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Viewing your email headers is similar to viewing a map that shows you the route your email takes when being delivered to your mailbox. They are a very useful way to discover the causes of many email problems that can occur on a hosting system.
How to read email headers
The following sections explain the various fields that comprise an email header and how to track the steps an email makes as it's delivered to its destination.
Understanding received message headers
In your mail program, you can select a message and then choose to view the message’s full header details. You must read it from the bottom up to see the message's path.
The following is a quick overview of the basic fields you’ll see for a basic message.
| Email header | Description |
|---|---|
| Return-Path | If the message is rejected, it is sent back to the email address listed here, which is also the sender of the message. |
| X-Original-To | The email address listed here is the original recipient of the email received. |
| Delivered-To | The email user listed (to the left of the @ symbol) is the user ID for the recipient email address hosted with DreamHost. The server listed (to the right of the @ symbol) is your DreamHost mail server that received this message. |
| Received |
There are Received by and Received from details listed on the headers. When checking your headers, the Received by indicates that it was received by the IP or server name when the message was originally sent. Received from would be the server that sent or relayed the email at any specific point in the header. |
| DKIM-Signature | This shows the DKIM signature if the email has one. All emails sent from DreamHost-hosted mail accounts are signed with DKIM. You can read more about DKIM signing in the DKIM article. |
| MIME-Version | This shows the MIME version, which has no relevance in troubleshooting mail delivery. |
| X-Received | This shows the message being received at the first server, where an ID is applied to it so the message can be tracked. |
Using a third-party tool to help you analyze headers
There a various tools you can use to help you evaluate the message headers of a message: