Office 365 Public CDN really anonymous accessible?

[Benjamin Stierle]

Hi everyone, 

I'm a bit confused with the Public CDN option. For my understanding if you setup a public cdn all the files that are allowed (IncludeFileExtensions CSS,EOT,GIF,ICO,JPEG,JPG,JS,MAP,PNG,SVG,TTF,WOFF) are accessible anonymous. This is also what is documented under https://docs.microsoft.com/en-us/office365/enterprise/use-office-365-cdn-with-spo

I have setup the public cdn for a custom library and uploaded a jpg file. I can see from developer tools the file is loaded via https://publiccdn.sharepointonline.com/<mytenant>/sites/SiteCollection/cdntest/myfile.jpg?width=1600

if I browse the url while I'm authenticated it opens the file. If I browse the file while I'm not authenticated it shows an access denied. 

My question is, are these files really accessible via Internet if I have the url? or what is definition of anonymous? 

kind regards   

[#2]

Hi @Benjamin Stierle - how are you testing this?

If you're just entering the address to the image directly in the browser, it won't work:

"You cannot test CDN URLs directly in a web browser because you must have a referer coming from SharePoint Online. However, if you add the CDN asset URL to a SharePoint page and then open the page in a browser, you will see the CDN asset rendered on the page." - from this Microsoft documentation