Email - content type 'multipart' - what does it mean?

hi guys,

We have had some issues with an email template recently. We created an email template which has been designed as responsive, using a service called Inkbrush and sent the email as a test to ourselves. The template turned out absolutely fine when received. When we looked at the header of the email, the encoding section, it had the below:

Content-Type: multipart/alternative;
boundary="--==_mimepart_564b67cddcf18_33ff6907d1e84329de"; charset=UTF-8
Content-Transfer-Encoding: 7bit

However, when we copied the same template onto our servers on the Amazon side which used a the Postfix service to send the email via our php mailer, the template arrived with some broken links with pictures with red crosses on them. The encoding on it was:

MIME-Version: 1.0
Content-Type: text/html; charset=UTF-8

What I wanted to know is whether the multipart being inserted into the actual first email being sent could be affecting everything? Also, how important is 'multipart' and what does it mean?

Thanks for helping
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Julian HansenCommented:
The multipart means that the message contains multiple sections separated by the boundary
boundary="--==_mimepart_564b67cddcf18_33ff6907d1e84329de"; charset=UTF-8

Open in new window

The boundary can be anything but must be unique to the message i.e. you don't want your bondary text to be something that could be in the message body.
The boundary determines the start and end of each section.

So, for instance, if your email has a text part an html part an embedded image and an attachment each of these will be loaded in a different section with appropriate encoding separated by lines of text that match the boundary string.

So yes in all likelihood the multipart header is important.

You will need to setup your email sending code to insert the appropriate message boundaries and encoded sections.

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
Dave BaldwinFixer of ProblemsCommented:
It is very important.  It is used as a separator for the different parts of an email like 'plain text', 'HTML', and embedded images.  This page has a simple explanation:
YashyAuthor Commented:
Do you know what the name of the file is to add the 'multipart' into on a linux instance? I believe this is a php file.

Thanks for helping me, much appreciate it.
Julian HansenCommented:
I don't understand the question?

The multipart is included in the message.
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today

From novice to tech pro — start learning today.