Firewall transformation work is rarely difficult because of rack space. The difficult part is understanding what the existing policy actually does and deciding what should survive into the new environment.
Patterns used in project delivery
- Inventory objects, routes, VPNs, and security rules before transformation.
- Separate site-specific values from reusable policy intent.
- Use automation where configuration patterns are repetitive.
- Generate reviewable output rather than pushing blind changes.
- Validate policy and traffic in stages with rollback available.
This note draws on client-confidential multi-vendor firewall migration and automation case studies.