Exchange Server & Outlook. HTML/Text format

[KobusDJ]

I'm running Exchange Server with all clients on Outlook.

Lately all mail from external senders, are stripped of the HTML formatting.

Sending internal mail in HTML format.... clients receive in HTML format. No problem. Even the older mail (before the problem started) is still in HTML format.

Where do I look for the problem? The ISP use QMail (I think ?) to forward to us. They claim that the problem is not with them.

Everything to do with “mail formatting” on my Server is set to “Both” (Text and HTML).

 

[Claymore]

Exchange should handle any HTML/plain/RTF mail that comes in, without modification.

 

[KobusDJ]

Exchange should handle any HTML/plain/RTF mail that comes in, without modification.

That is how I know it as well. Do you think the ISP's forwarding may have something to do with it?

 

[Aqox]

What software did you install/upgrade before the first incident?
Anti-Virus programs can also bugger around with mail messages... just an idea

 

[KobusDJ]

Aqox, nothing new.

I thought about that, but wouldn’t “other software" influence all mail….. not only the external incoming mail?

 

[bekdik]

Sounds like a firewall or mail spam filter, probably in the DMZ which is converting the html.

 

[KobusDJ]

Mail comes from ISP, through PfSense router, directly onto the Exchange server. No spam filter installed.

 

[bekdik]

Then get your ISP to check Pfsense settings and CONFIRM that no changes have taken place.

 

[KobusDJ]

I manage the PfSense setup. It merely forwards the mail ports.

 

[bekdik]

Then maybe your ISP has subscribed to something like SORBS without telling you.

 

[KobusDJ]

Thanks, will talk to them on Monday.

 

[koffiejunkie]

Then maybe your ISP has subscribed to something like SORBS without telling you.

Sorbs is in the blackmailing business, not the mail-forrmat-conversion business.