picture of tbs certificates
picture of tbs certificates
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When is a certificate required for Office 365?

Office 365 allows you to deport part of your services to a Cloud solution hosted by Microsoft. However, it might be necessary to acquire a certificate issued by an official certification authority and to deploy it in Office 365. Here are the main cases:

  • Exchange on-premises
  • Single sign-on (SSO) (for both the Active Directory Federation Services (AD FS) federation servers and AD FS federation server proxies)
  • Exchange Online services, such as Autodiscover, Outlook Anywhere, and Exchange Web Services
  • Exchange hybrid server


For the Exchange plans requiring certificats, the procédure is the same as a conventional Exchange server.


The main certificate to acquire is the one that authenticates and encrypt communications for the federation service (FS) of each ADFS instance. The same constraint applies to proxy federation servers.

It is also possible to acquire a token signature certificate if that is required to your organization. Microsoft recommend to contact Office 365 to make the change, this certificate being critical to the infrastructure.

See also