Deep dive # 2: How to configure Exchange on-premise Server hybrid integration with Office 365/Azure Infrastructure and test REST API calls?

So this post is dedicated for Exchange/Office 365/Azure administrators, as they came back after checking the deep dive # 1 blog with few queries.

/api virtual Directory:

• CU3 introduces a new virtual directory to support the REST API, the /api virtual directory.
• So the API virtual directory is available in Exchange 2016 CU3 or newer only.
• If you have deployed a firewall or application gateway that inspects and restricts access based on the virtual directory being accessed, you will need to update the appropriate settings to allow access to the REST API virtual directory.
• About default Exchange Virtual Directories please refer: https://docs.microsoft.com/en-us/exchange/clients/default-virtual-directory-settings?view=exchserver-2019

Auto Discover settings:

• The REST API takes advantage of a new Autodiscover method for determining authentication and mailbox location.
• In order to ensure REST API applications can access the on-premises infrastructure correctly, you will need to update the appropriate firewall or application gateway settings to allow access to the /autodiscover/autodiscover.json virtual directory file.

The Hybrid Configuration Wizard:

• The Hybrid Configuration Wizard (HCW), performs the necessary configuration steps to support REST API integration with on-premises environments.
• Specifically, the HCW adds a new authentication provider and registers a hostname with the Azure security token service.
• For additional info refer: https://blogs.technet.microsoft.com/exchange/2015/09/04/introducing-the-microsoft-office-365-hybrid-configuration-wizard/

Hope this helps.