I’m Arthur Hanauer from the SAP Product Support team.

I’m writing this blog to provide a general overview on how a custom MIME header would be set up for email servers, as this is something that may be needed when you are using different email approach’s, specially when working with the SAP Cloud for Customer system and supporting emails in BCC.

For more details you can refer to the blog post Handling of Multiple – Channel E-mail addresses in the TO or CC field

It is important to highlight that the following content are generic steps which need to be followed outside of an SAP environment and are purely for reference, hence, SAP cannot commit on specific steps for any email providers and servers as these may change. The goal of this blog is to serve as a guide on what needs to be done, but should not be taken as the official documentation of any email providers.

In general, to set up a custom MIME header for your email server will involve configuration changes on your email server software, as these MIME headers are used to provide additional content for email messages, such as attachments, character encoding, email addresses, etc.

Below is a sample of steps that you can follow, but the exact steps will change depending on the email server software you use (e.g. Microsoft Exchange, Postfix, Sendmail, etc.).

1. Access your Email Server Configuration:

The first step is to log in to your email server administration console or configuration files. The way this login will be made may depend on the email server you are using.

2. Locate the Configuration File:

Next, you need to identify the configuration file or section that you can make the changes to the email headers. Usually this can be a main configuration file or a specific file designed for MIME settings.

3. Add or Modify the MIME Header:

Now it is time to add a new header or even modify an existing one. The syntax may change depending on the provider used, however, generally it is required to specify the header name, its value and any additional parameters.

It would look something like:

• • X-Custom-Header: CustomValue

4. Save and Apply the Changes:

Now you can save the configuration file, so that all changes are applied.

5. Restart the Email Server:

In general, it is required to restart your email server, so that the changes take effect, so you need to make sure this process is followed on the email server or related email services.

6. Test the Custom MIME Header:

To test if everything worked out fine, you can send an email and see on the email MIME if the custom MIME header is included as expected. This can be verified by checking the email source or header.

To provide a more specific example of the above general steps, below are some steps an email server administrator could follow to create or modify the custom MIME header on a Microsoft Exchange email server.

For the Microsoft Exchange, the process involves modifying / creating a transport rule:

1.Access the Exchange Admin Center (EAC):

As a start, it is required to log in to the Exchange Admin Center, which is used to manage the server. The URL would look like https://<server_name>/ecp

2. Navigate to the Mail Flow:

Once logged in, navigate to the Mail Flow option on the left side menu.

3. Create a New Transport Rule:

Click on Rules and then + to create a new rule.

4.Define the Conditions (If Necessary):

This is an optional step, however, if required, you can define the conditions that, once met, will trigger the transport rule. Conditions can be for instance a specific sender, recipient, keywords on the email subject or body, etc.

5. Define the Actions:

Within the Do the following section, click on Add Action and then select Set the message header to this value.

6. Configure the Custom MIME Header:

Now, in the  Header Name field, you can enter the name of the custom MIME header you would like to use e.g. X-Custom-Header.

In the Value field, you can then add the desired value for your custom MIME header e.g. CustomValue

7. Save the changes and Enable the Rule:

Once the header name and value are set, you can proceed to save the rule settings, enabling it or scheduling its enablement for later.