Office 365 external access restriction

Hello,

We use on premise Exchange and use federated accounts via Centrify for our Office 365 access for our employees.

Currently, the Office 365 restriction (when accessed from external) is achieved by defining the IP addresses in the Corporate IP range. After that, it will prompt for MFA.

If we move Exchange on premise to Exchange Online, how best to restrict Office 365 access when accessed from external network other than corporate network?

Is there any option apart from Corporate IP range? How do we go about it?

Regards,

Ganesan