Since the invention of electronic mail (e-mail) back in the 1960s, it has been used for business, military and personal purposes. The need to send messages via the internet has grown ever greater as the world becomes increasingly mobile. Most people have a mobile device connected to the internet and send and receive emails every hour, or even every minute.

Sending emails and ensuring they are delivered without issues has become a vital necessity and requirement for business owners. Scripts or applications that use the PHP mail() function to send messages are particularly vulnerable to failed deliveries. WordPress is the leading CMS on the market, and failed deliveries can have a detrimental effect on your brand. We recommend using YaySMTP to provide SMTP authentication for sending emails, ultimately increasing the chances that your WordPress emails will reach their recipients.

In this article, we will introduce you to the three main components of an email, in the hope that you will gain an understanding of how emails are structured. Understanding these parts of an email can help you create effective anti-spam filters using the filters available in cPanel. It can also significantly reduce the likelihood of you falling victim to a phishing attack.

The email ‘envelope’

To manage delivery to different recipients more efficiently, the software sending the message uses the concept of an envelope. This envelope is similar to the physical envelopes used for postal correspondence. It contains the sender and the recipient(s), which the sending server needs in order to deliver the message. If there are multiple ‘TO:’ addresses, each server receives its own envelope containing ONLY the address located on that particular server. For example, if you send an email to the addresses user1@domain1.com and user2@domain2.com, the outgoing server will see the two addresses to which the emails are to be delivered. If you send the message to user1@domain1.com, that server will NOT see the address user@domain2.com, and vice versa.

Generally, the information provided in the envelope is also included in the email header. Occasionally, discrepancies may arise because a malicious organisation has forged the header in an attempt to steal sensitive information.

The email header

The header is the part of an email that always appears before the body and contains specific routing information for the message. It consists of the sender, the recipient, the date sent and the subject line. It may also include other optional data, such as the receive and send timestamps of all servers involved in the email transmission. In addition, it may display the script that sent the email and the spam score, if you are using anti-spam software.

Please bear in mind that this part of the email is a regular target for exploitation by hackers. By falsifying the information in the header, their aim is to steal your sensitive data, such as credit card details.

The body of the email

The body is the part of the email that follows directly after the header. It contains the subject of the message, as well as everything else the sender has written in the text field and any files they have attached.