A project I am currently heavily involved with is to implement email archiving. Because email archiving can alleviate Exchange storage constraints it is a feature many mail administrators get excited about. Even more exciting is the prospect of a 3rd party offsite archive as storage and system maintenance is someone elses problem.
The project was running smoothly and the initial implementation had progressed very well. Email was successfully journaled to the archive and end users were able to read and action content. However some email content was only viewable as plain text and clearly this had to be resolved asap.
Only some content displayed as plaint text? Was there a pattern? There was and it seemed email that had been sent or received with an external recipient was able to be viewed correctly where as internal only communications were affected. There are a couple places where email may be delivered to the archive and this includes the email security gateway and Exchange journaling. Email routing via the security gateway takes precedence over Exchange when arriving to the archive and these emails were not affected. Something was happening within Exchange to cause plain text only email to be sent to the archive.
Affected emails displayed as plain text and images no longer displayed within the email and were now attachments. Below is an example
I quickly start looking through Exchange configuration in an attempt to find anything that may indicate what caused the problem. After sifting through transport configuration, browsing logs, reviewing send and receive connectors nothing stood out. Realising remote domains configuration also affects formatting I took a look via the management console. Nothing specifying plain text was misconfigured.
Next I looked through Outlook client settings even though I was confident this wouldn’t have any affect on the problem. Still I wanted to see if i could do something that may change what I see in the archive. No luck here.
The focus returned to troubleshooting Exchange server and this time remote domains configuration was reviewed using Exchange management shell and this returns more detail than is viewable in the management console and it revealed what may be the root cause.
get-remoteDomain | fl identity, domainName, contentType
ContentType can be configured as MimeHTMLText, MimeText, or MimeHTML. A quick call to PS to confirmed this would need to be changed from MimeText to MimeHTMLText however I was a little hesitant to make a change during business hours and only internally journaled email was affected.
The solution was to create a new remote domain for journal specific email and configure the correct content type. I had no issue implementing this change during business hours and it was performed using the following command
new-remoteDomain -identity JournalEmail -domain email@example.com
When creating a new remote domain the content type is automatically set to MimeHTMLText so no further changes were required after the new journal remote domain configuration was made. So why was default remote domain set to MimeText? Obviously a legacy setting that hasn’t changed as Exchange versions have been upgraded. Why did this only affect journal email and nothing else? I haven’t dug that deep yet however problem resolved and now archive content displays using the correct format.
And remember to always check configuration using the management shell as it returns more detail than the console.