Understanding Email Headers

Everyone knows how to send and receive emails but only a few understand the concept behind the process. Emails are normally not send directly from your machine to the recipient. Mailservers that are setup by your ISP for instance process incoming emails and send them on their way. This information is stored in the headers of the email. Understanding email headers helps you identify spam directed at you.

The article “reading email headers – all about email headers” gives you an in depth overview about email headers. Everything is explained with examples which makes it easy to follow through, even for people who lack the tech background.  It begins with a introduction “where mail comes from” and details “mail protocols” thereafter. The final part consists of a list of common mail headers which is great if you want to understand a certain part of the header.

Update: The guide is divided into four chapters. Displaying email headers explains how you display email headers in popular email clients such as Outlook, Netscape or Eudora. Please note that the article has been written in a time where popular clients like Thunderbird have not been created yet.

Received headers detail the emails origin and the route it took to get to you. These information are displayed in reverse order which means that the last received header in the email is in fact the first that received the email, and the first in the listing is usually the mail server of the email provider.

The last received header details what you can find out about the first server that processed the email. This can be helpful to identify the origin of the email which in turn can be used to report an email as spam or malicious.

Other headers finally lists other common email headers that you may come upon in emails.

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Author: Martin Brinkmann, Thursday June 15, 2006 -
Tags:email headers, emails, spam