emailgtw - is it possible to change the SMTP transmission formats, for example to disable multipart or affect the MIME-Type?

Products

• DX Unified Infrastructure Management (Nimsoft / UIM)

Issue/Introduction

In emailgtw 2.84 and prior, emails are sent using plaintext/ASCII, but the MIME-Type transmitted to the SMTP server is TEXT/html.

Starting with emailgtw 2.90, emails are sent in multipart MIME format by default.

In emailgtw 2.91 we have the ability to disable multipart, but when doing so, the MIME-Type also changes to TEXT/plain.

Is it possible to have more control over this? What options are available?

Environment

Release : 20.4

Cause

Multipart is compatible with most modern email clients but in some cases, it may be desirable to send emails in plaintext format - either to maintain compatibility with legacy systems or perhaps to integrate with automated systems that receive the emails sent.

 

Different versions of emailgtw allow for additional control over these options as documented here.

Resolution

In emailgtw 2.84 and higher, by default, emails are sent in HTML format.

You can change this by setting "use_html" to "no" in emailgtw.cfg which will cause emails to be sent in plaintext format, with MIME-TYPE still set to TEXT/html.

In emailgtw 2.90 and higher, emails are automatically sent with MIME-TYPE set to "muiltipart" regardless of the above setting.

In emailgtw 2.91 and higher, it is possible to control the multipart formatting option.

To change this back to plaintext format (as was the default in 2.84) you may set the following key/value in the emailgtw cfg, <setup> section:

disable_multipart = yes

In emailgtw 2.92 and higher, it is possible to control the MIME-Type even further.

You can add a key to the setup section in emailgtw.cfg:

    use_html_content_type = 1 

This defaults to 0, so TEXT/plain will be used by default.  When set to 1, then TEXT/html will be used.

This is independent of the "use_html" setting.

 

 

 

Additional Information

Between releases 2.84 and 2.91 there were a number of changes to emailgtw which resulted in some changes to the default delivery formats; many customers would not be impacted because ultimately the e-mail client used to receive the emails is responsible for displaying them and in the majority of cases the display did not change.

However, customers who were sending messages through emailgtw their own customized HTML templates may have noticed the display changing between releases, especially where "use_html" is set to "no" and "disable_multipart" is set to "yes."

emailgtw 2.92 restores the default behaviors to what they were in 2.84 for the most part.

As of August 7 2024 this version is not yet released but is under development. 

For now, customers who experience display issues with HTML templates should stick with emailgtw 2.84 if possible.