Office 365 Namespace Requirements

Please find a list of typical namespaces that are required when setting up and installing Active Directory Federation Services (ADFS) 2.0 and rich coexistence/hybrid with Office 365





On premise SMTP Namespace

On-premise SMTP namespace

Online Tenant Namespace

Name of the namespace given by Microsoft when the tenant is created

Service Namespace

SMTP mail routing namespace for determining where the mailbox is located.

Delegation Namespace

Federation delegation to the Microsoft Federation Gateway. Allows sharing of free/busy between external organisations

Federation Service Name

ADFS name that O365 will redirect clients to


Autodiscover service for Outlook client on-premise


Autodiscover service for Outlook clients migrated to O365

Written by Daniel Kenyon-Smith