The scenario is this:
- We have a Web Service which is hosted in Intranet Network
- Plan is to expose Web Service to Internet so SharePoint Online Hosted App can access it
Problem is security. If there is no authentication method for the Web Service, hackers can easily call Web Service if they know the URL.
Is there a way to 'whitelist' requests coming from SharePoint Online? And how do we know which IPs is it?
Does the SharePoint Hosted App even mark as originating from 'microsoft servers'? Or the App will have IP address originating from wherever the User is?