Routing in FortiGate Firewall LAB – Zero to Hero

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The "Routing in FortiGate Firewall LAB - Zero to Hero" PDF is a comprehensive guide that walks you through the fundamentals and advanced concepts of routing in FortiGate firewalls. Here's a structured summary of the key insights:

🔧 Core Concepts and Configuration

1. FortiGate Interfaces & DHCP

• Interfaces connect internal networks and the internet.
• FortiGate can act as a DHCP server, assigning IPs, gateways, and DNS dynamically.

2. IP Routing Basics

• Routing Table (RIB): Contains best routes (static, connected, dynamic).
• Forwarding Table (FIB): Used for actual packet forwarding.
• Route Lookup: Determines the best path based on destination IP.
• Routing Precedes Security: Routing decisions are made before firewall policies are applied.

📘 Routing Types and Attributes

3. Static Routing

• Manually defined routes.
• Can use named addresses (subnets or FQDNs).
• Default route: 0.0.0.0/0 used when no specific match is found.

4. Internet Services Routing (ISDB)

• Routes traffic to specific services (e.g., Netflix) via specific WAN links.
• ISDB routes are policy routes and override regular routing.

5. Route Attributes

• Distance (AD): Lower is preferred.
• Metric: Used within dynamic protocols (e.g., OSPF, BGP).
• Priority: Breaks ties between equal-cost static routes.
• Weight: Used in weighted ECMP for load balancing.

🔄 Advanced Routing Features

6. ECMP (Equal-Cost Multi-Path)

• Allows multiple routes with equal cost to be active.
• Load balancing algorithms:
  • Source IP
  • Source-Destination IP
  • Weighted
  • Spillover
• ECMP is useful for high availability and bandwidth aggregation.

7. Reverse Path Forwarding (RPF)

• Protects against IP spoofing.
• Two modes:
  • Feasible Path (Loose): Any matching route.
  • Strict: Must be the best route.

🧪 Hands-On Labs

Lab 1: Route Failover

• Configure two default routes with different distances.
• Simulate failover by disabling the primary interface.
• Use logs to verify traffic rerouting.

Lab 2: ECMP Routing

• Configure two default routes with the same distance and priority.
• Change ECMP algorithm to source-destination IP for better load balancing.
• Use CLI tools and logs to verify traffic distribution.

🧠 Key Takeaways

• Routing decisions are foundational—they determine how traffic flows before any security policies are applied.
• Understanding route attributes (distance, metric, priority) is crucial for troubleshooting and optimizing routing behavior.
• ECMP and SD-WAN offer powerful tools for load balancing and failover, but require careful configuration.
• Policy routes and ISDB provide flexibility for routing based on services or custom criteria.