What Are Email Headers?

Posted on May 23rd, 2022
by Editorial Team

An email header is a fragment of code that contains the information needed to verify an email message. Avoiding phishing attempts is as simple as checking the verification results before following a link in a message. Headers always precede the body of an email.

Additionally, understanding email headers aid in the launch of email campaigns. By sending test emails and checking their headers, you may figure out what email security to add to keep communications from ending up in the spam bin.

The processes for viewing an email header are nearly identical across all email services. There are, however, some changes in the first stage.

What is an email header?

An email header is more than just the to, from, date, and subject lines that appear before the body of the email. Because every email message has an email header, headers are also important for tracking an email's journey.

When sending an email from one address to another, it will pass via mail transfer agents (MTA). As a result, email headers will reveal whether the email was sent to other email addresses before reaching its intended recipient. Users should not open the email if the header information is introduced to be suspicious.

Headers give information about the data transmission by utilizing metadata.

Emails are made up of three primary parts:

  1. Header: Email headers are unique sets of information that include important information for mail delivery.
  2. Body: The email's body comprises the content and attachments of your message.
  3. Envelope: The email provider and outgoing server employ the envelope, which is invisible to both the sender and the destination, to connect and transmit the intended message email account.

Some email header features (metadata) are reachable from the top of the email, but you must access your custom header separately.

You can see which servers, ISPs, and email services the message passed through by looking at the email headers. You may quickly determine whether the email transfer was secure and whether it arrived at its desired target without faults or modifications.

Why do you need an email header?

Spam is protected by email headers.

The header contains many fields that enable email service providers (ESPs) to distinguish between spam and legitimate emails. The header information is analyzed by ESPs to assess whether the message is legitimate and should be delivered to the intended recipient.

These ESP methods guard your email account and personal information against phishing and spam communications.

The Sender/Receiver Information is clarified in the Message Header.

The From (message origin) and To fields are seen in every email header. There's also a Subject box and a Date indicator, which show when a new message was delivered and at what time.

You wouldn't be able to view origin details or identify the email's sender or receivers without the info from the message header, and you might not be able to tell if the message body (email body) includes legitimate information without it.

Email headers aid in the tracking of an email's path.

When a user sends an email message, it starts with a sending mail server and travels via many Mail Transfer Agents (MTAs) finally arriving at the intended destination.

The mail server automatically "stamps" this new message with custom header lines like the receiver, date, and time of the letter as it travels through an MTA.

This header information will assist the recipient in tracking the email's path to its destination by allowing them to examine all of the MTAs the email traveled through on its way there. When trying to check message source details and actually track down the origin of harmful and spam emails, this is helpful.

Metadata of an email header

Metadata is a type of organized reference information that aids in the classification and identification of data attributes. The information about your communications that may be discovered in email headers is referred to as email metadata.

The code up until the tag is included in an email header. The following is a list of what can be found in any email header.

  1. From: Contains information about the sender. Keep in mind that phishing scammers and spammers frequently use false email addresses in this section.
  2. To: Displays the email address and name of the recipient. Email addresses in the "carbon copy" (CC) and "blind carbon copy" (BCC) boxes are also included.
  3. Date: Indicates when the email was sent. This date is usually displayed in the format day, dd month, yyyy hh:mm:ss in email clients.
  4. Return-Path: This is a required component that specifies the email address to which the machine will send its message. It will be used as the email address for receivers to respond to if no reply-to address is given.
  5. Envelope-to: This specifies that an email was sent to the address supplied on this line.
  6. Subject: The title or subject described by the correspondent in the subject line is included in the subject.
  7. Message-ID: When you write a message, you establish a unique string of characters and numbers called a message-ID. Although each message has an id Number, be aware that cybercriminals can make minor changes to this field.
  8. MIME-version: MIME-version is an acronym that stands for Multi-Purpose Internet Mail Extensions. It's an addition to the online email protocol that allows you to transmit and receive many forms of data files such as photographs, audio, and video via the internet, as the name implies.
  9. The Content-type: This field indicates whether the email is sent in text or HTML format. If you have an image or video, it will also appear.
  10. DomainKeys and DomainKeys Identified Mail (DKIM) Signatures: DomainKeys and DomainKeys Identified Mail (DKIM) signatures let email providers recognize and authenticate messages by associating the domain name with the email.
  11. X-Spam-Status: This tells you if an email is spam or not. The exact numerical score is also displayed. It will say "no" if it is not spammed.
  12. X-Spam-Level: SpamAssassin scores are denoted by asterix (*). It is beneficial to receive fewer stars since each star represents a step forward.
  13. Message Body: The primary content of the email is displayed in this field.

How to read an email header?

Depending on the email service provider, the layout and techniques for reading an email header differ (ESP). Examine it by looking at the email header and looking for the lines that interest you.

Gmail's Email Headers

Gmail is one of the most popular online email services, with over 1.5 billion active users globally. It's no surprise that Google constantly adds new features and capabilities to Gmail.

Select the Gmail message that contains the header you would like to view in your client.

email header

Once you see the message body, click on the three dots beside the "Reply" button to access the kebab menu.

In the dropdown menu, select "Show Original".

The longer header will appear in its original HTML format in a new window. Details about headers such as authentication statuses, IP addresses, MIME versions, and DKIM signatures can be viewed.

In order to install and view the header data individually, click on "Download Original". Alternatively, you may email the header data to your tech support team.


Sender and recipient information is included in an email header. In addition, by determining the message path, consumers can determine whether a message is valid and safe. Email headers contain information that can help you avoid malicious attacks.

Before clicking on any links in an email message, check the header.

Understanding an email header's benefits and how to interpret it may help you defend yourself from phishing attacks.

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