Firewall is no longer adequate. It requires a multi-pronged defence-in-depth approach across people, process and technology.
The security perimeter dissipated long ago. Need to approach security with a Zero Trust mindset
We are no longer building just a perimeter around what’s high value. You need to understand who or what is accessing your data and from where.
Also add 2 factor authentication and add IP restrictions where possible. Implement data segregation.