An EML (Electronic Mail) file is an open file format used to store individual email messages. It is a standard file format often associated with email clients like Thunderbird that follow the MIME (Multipurpose Internet Mail Extensions) standard. EML files contain the complete content of an email message, including the text, attachments, and metadata.
An email internet transport header, also known as an email header or message header, is a block of metadata information that provides details about the origin, route, and content of an email message. This information is not typically visible in the body of the email when you read it but can be viewed by accessing the email’s header section.
Email internet headers are usually not visible to users. A useful tool for managing EML files and viewing the internet header is a Pst Viewer Pro (formerly known as EML Viewer Pro) by Encryptomatic LLC, a U.S. based software developer.
Here are some key components typically found in an email internet header:
- Return-Path:
- The email address to which bounce notifications and delivery errors are sent.
- Received:
- This section contains information about the servers through which the email passed on its way to the recipient. It includes details like the server’s IP address, timestamp, and authentication information.
- From:
- The email address of the sender.
- To:
- The email address of the recipient.
- Subject:
- The subject line of the email.
- Date:
- The timestamp indicating when the email was sent.
- Message-ID:
- A unique identifier assigned to the email for tracking and reference purposes.
- MIME-Version:
- The version of the Multipurpose Internet Mail Extensions (MIME) standard used in the email. MIME is a standard that extends the format of email messages to support text in character sets other than ASCII, as well as attachments of audio, video, images, and application programs.
- Content-Type:
- Specifies the type of content contained in the email, such as text, HTML, or attachments.
- X-Headers:
- Additional custom headers that may be added by email servers or applications for specific purposes.
The email header is crucial for various reasons, including:
- Routing Information: It shows the servers and paths the email took to reach its destination.
- Authentication: Some headers provide information on email authentication methods used, helping to verify the legitimacy of the sender.
- Spam Filtering: Email headers can contain information used by spam filters to assess the likelihood that an email is spam.
- Troubleshooting: When dealing with email delivery issues, the header can be analyzed to identify potential problems in the routing process.
To view the email header in most email clients, you can look for an option like “View Source,” “Show Original,” or “View Message Source.” Analyzing email headers can be useful in understanding the journey of an email and in troubleshooting email-related problems.
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