Kurt Shintaku's Blog

We recommend that you harden your Azure AD Connect server to decrease the security attack surface for this critical component of your IT environment.

Following these recommendations will help to mitigate some security risks to your organization.

• DOCS: Harden your Azure AD Connect Server
  https://docs.microsoft.com/en-us/azure/active-directory/hybrid/how-to-connect-install-prerequisites#harden-your-azure-ad-connect-server