Exchange Free/Busy Calendar Sharing
Since Exchange 2010, Microsoft have introduced the Microsoft Federation Gateway. This allows companies to setup a trust to Microsoft which can be used to gain scheduling information with a third parties once policies have been configured on both parties Exchange environment.
This looked like a pretty straight forward task and certainly a LOT easier than setting up direct trusts or sharing keys. Unfortunately it wasn't quite that straight forward.
These were the Issues we ran into and the relevant fix.
1. Cannot create Organisational Relationship for third party. Also when running get-federationinformation Powershell cmdlet, it errors.
|Works from Lab into Enterprise|
|Fails from Enterprise into Lab|
FIX = Enable Outlook logging, attempt the Free/Busy test and in resultant FB log file it shows a proxy 407 authentication issue. The fix is to allow unauthenticated access to the EWS path from all the CAS servers.