It was recently brought to my attention that select attachments are getting stripped from E-mails. .docx, .xslx, .pdf 's all come and go with no issue. However, emails that contain other attachments (in particular .sldprt,.slddrw (SolidWorks) and .7z) are getting stripped.
When the emails arrive, they have no attachment at all (not even winmail.dat). This happens regardless of whether I sent these emails internally or externally.
Now, this is where things start to get confusing. If I send the email to both an internal and an external contact at the same time (tested using my work email and my personal gmail) and it contains one of the problem extensions, I can sometimes get the attachment. If I send it to both an external and internal and then attach BOTH a .docx and .sldprt it will go through all the time.
I've disabled personal firewalls, checked for spam filtering on our server, but haven't been able to come up with anything conclusive. It's just a lone 2013 server, no Edge Transport, so I am unable to do anything with Get-AttachmentFilter.
I wasn't the one who set up the exchange server, and my manager tells me that there shouldn't be a filter in place, but I'm starting to run out of ideas.
Thanks!
