What is an email header and why it is a very important yet often overlooked space. It’s where the message’s authentication codes are stored.
Initially, it includes the date and time of sending, server identifications, email subject, and the names of both the recipient and the sender.
However, the email header is not limited to just this information.
Header data is logged and allows for the visualization of the entire message’s route. Each email has a unique header that records its path so that its identification can be easily seen.
Every email sent must pass through the Mail Transfer Agent (MTA), which catalogues all deliveries. This service permeates the header of each message.
And the header shows, before the message reaches the provider, which recipients also received the email. Thus, the provider analyzes if that message passed through any suspicious places.
This data is essential for online security, aiming to prevent cybercrimes like phishing.
On the other hand, email verification is another fundamental item to ensure the protection of email marketing campaigns.
Email lists containing invalid addresses lead the entire list to the spam box, and the sender’s IP is classified as a spammer.
Internet security is crucial for any business. Only work with sanitized and secure email lists.
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Next, see why the email header is relevant to your security.
Email Header and Online Security
Provider spam filters pursue suspicious emails. And the route of a message can be a dubious element.
Before entering your inbox, an email knocks on your provider’s door, which will decide whether to open it or not.
Similarly, when a provider opens the door, it decides where to forward the message, which can go to the inbox or to the spam folder.
Only Gmail has four destination folders: the inbox, promotions, social, and finally, the unwanted spam.
The email header is crucial for the email to pass through the providers’ spam filters, as all legitimacy and message route information are recorded there.
Keep reading to see how to analyze the metadata of an email header and identify possible irregularities.
DKIM, SPF, and DMARK signatures
These are authentications that can only be seen by providers, for the purpose of identifying email senders.
SPF, DKIM, and DMARK certificates attest that the email is legitimate and was sent by the domain owner of the message. This way, nobody can send messages on behalf of a sender that does not belong to them.
If you work with email marketing, pay attention to these certifications, which comply with best practice recommendations.
Sender’s name
It is the “From,” that is, where the email comes from. This space is for identifying who sent the message, and here you can identify if the source is trustworthy or not. Do you know this sender?
Many scammers send emails as if they were from your bank, but with a letter swapped in the address. Pay attention to the sender of the message, as it may be part of a phishing scam.
Phishing is a cybercrime that provides access to bank passwords and other email recipient data.
Recipient’s name
It is the “To.” This is where your address is included as the message recipient. Here, it is also possible to see the Copy addresses, that is, additional contacts who will also receive the message.
In this space, there are also Blind Carbon Copy (BCC) emails, where you and other readers cannot access. However, this data is recorded in the email header and is also available to providers.
Date and time
This data is useful for users to see the message’s timeline. This is common in the corporate environment, where long conversations are held via email. It also serves to keep records by providers, in order to maintain online security.
Email subject
One of the most important parts for those working with email marketing. In other words, it is the first contact recipients will have with the message, and the email subject will determine whether the message will be opened or not.
Thus, the user prioritizes emails of interest.
Reply / Forwarding
In addition to the functionality of replying or forwarding the email, this space is an important source of information for the provider to record the email’s route.
Content type
This data informs whether the message is in text or HTML, and also shows if there are images and/or videos in the email.
Message ID
Each email has a unique identifier (a code of exclusive letters and numbers) created to avoid duplication. It is important to note that, even so, this space can suffer interference and falsification.
Reasons why the email header is important
- Online security: protection against spam, phishing, and other cybercrimes.
- An email header that complies with best practices ensures the sender’s reputation with email providers. This helps campaign deliverability.
- Your emails can be tracked, allowing you to identify delivery issues.
FAQ – frequently asked questions about email headers
The header contains the names of the sender and recipient, the date and time of sending, the email subject, and other technical information, which, in turn, can only be accessed by providers.
The header retains ID and route information, which are unique to each email. This allows the visualization of a message’s behavior and prevents it from being used to carry out cybercrimes like phishing.
These are all the information present in the email header, encompassing both technical and non-technical references.
Basic data, displayed in the headers of most providers: “From”; “To”; “CC”; “BCC”; Forwarding”.
Both for the user and the provider, the header is important for online security, email marketing best practices, and campaign performance analysis, such as delivery rate.
SPF, DKIM, and DMARK signatures; content type, and message ID.
