I have two servers with virtually identical setups (the second that is working has been around longer than the other). For my newer server when I just put an address to a PDF in the browser it launches a download dialog. If I put the same address (just changing the server name) in the browser to my older server it displays in the browser just fine. There is no difference between the files themselves. The issue is I want to display these pdfs in an iframe on a page and the same thing is happening with the iframe (the new server launches a download instead of the pdf just showing in the frame).
Any ideas would be most appreciated!
Once I started looking into SP 2010 as being the cause I found that there is a default setting for all new 2010 sites that causes this issue. The following blog post had the most complete information on the subject:
Please indicate web server your are using
Initial suggestion may be this has to do with MIME-TYPE setup