Enterprise Firewall & Network Segmentation
SECURITY
2021 · Security Engineer
Security · Network
Overview
Firewall and network segmentation program isolating critical services, enforcing policy and reducing lateral-movement risk across the estate.
The Challenge
Flat network with no segmentation exposed critical services to lateral movement.
Constraints
Flat networkLateral movement riskCritical services exposureMinimal disruptionCompliance pressure
My Role
Security Engineer — I owned the technical delivery, architecture decisions, implementation phases and operational handover for this engagement.
Measurable Outcome
Segmented estate with enforced policy, reducing incident surface.
A
ARCHITECTURE
Internet
↓ Firewall
↓ Segmented Zones
↓ Policy Enforcement
↓ Access Networks
↓ Users / Services
B
SOLUTION
Firewall and network segmentation program isolating critical services, enforcing policy and reducing lateral-movement risk across the estate.
Technology
FortinetSophosCiscoLinux
Security Considerations
- Zone segmentation
- Policy enforcement
- Least privilege
- Monitoring & alerting
- Incident containment
C
IMPLEMENTATION
Phase 1 — Crown-jewel discovery
Phase 2 — Zone & policy design
Phase 3 — Phased segmentation
Phase 4 — Monitoring & alerting
Phase 5 — Ongoing governance
D
RESULTS
Segmented estate with enforced policy, reducing incident surface.
MEASURABLE OUTCOME
2021
DELIVERED
4
TECHNOLOGIES
E
WHAT I LEARNED
Segmentation turns a breach into a contained incident — a few well-enforced rules about what can talk to what beat a hundred rules nobody maintains.
F
GALLERY
FIG 1
Winbox Interface
FIG 2
Network Rack
FIG 3
Firewall & network segmentation