I have an environment setup with 10 onsite and 20 offsite users. All using Office 365 E3 with SharePoint and exchange online.
NOTE: The offsite uses have VPN access but never use it, forcing them to use it is not an option.
We currently have ADFS working with no problems, but we are looking to implement two factor authentication .
What types of two factor authentication are available and what do you think the best solution would be?