A firewall migration should be treated as a controlled infrastructure project, not a simple configuration copy.
Before the change
Create a tested migration plan, validation checklist, rollback plan and communication window.
During the change
Implement in controlled phases and validate critical traffic paths rather than assuming a successful boot means a successful migration.
After the change
Review logs, performance, policy hits and VPN status. Update documentation immediately so the new state becomes the known baseline.
This article is general technical guidance. Actual architecture should be validated against the organization's requirements, risk profile and existing infrastructure.