Configuring FortiGate as a DHCP Server and IP Routing

After completing this document, you will be able to achieve these objectives:

• Configure networking interfaces
• Configure FortiGate as a DHCP server
• Understand IP Routing
• Static and Dynamic Routing
• ECMP Load Balancing
• Lab Exercises for Practical Implementation

You Should Know:

1. Configuring FortiGate as a DHCP Server

To set up FortiGate as a DHCP server, use the following CLI commands:

config system dhcp server 
edit <interface_name> 
set dns-service default 
set default-gateway <gateway_IP> 
set netmask <subnet_mask> 
set interface <interface_name> 
config ip-range 
edit 1 
set start-ip <starting_IP> 
set end-ip <ending_IP> 
next 
end 
next 
end 

#### **2. Static Route Configuration**

To add a static route in FortiGate:

config router static 
edit 0 
set dst <destination_network> 
set gateway <gateway_IP> 
set device <interface_name> 
next 
end 

#### **3. ECMP (Equal-Cost Multi-Path Routing) Setup**

For load balancing across multiple routes:

config system settings 
set ecmp-max-paths 4 
end

config router static 
edit 0 
set dst 0.0.0.0/0 
set distance 10 
set priority 10 
set device port1 
next 
edit 1 
set dst 0.0.0.0/0 
set distance 10 
set priority 10 
set device port2 
next 
end 

#### **4. Verifying Routes**

Check the routing table:

get router info routing-table all 

#### **5. Reverse Path Forwarding (RPF) Check**

Enable RPF to prevent IP spoofing:

config system interface 
edit <interface_name> 
set rpf enable 
next 
end 

### **What Undercode Say:**

FortiGate provides robust networking features, including DHCP, static/dynamic routing, and ECMP for redundancy and load balancing. Key takeaways:
– Always verify routes using get router info routing-table all.
– Use ECMP for high availability across multiple WAN links.
– Enable RPF to enhance security against spoofed traffic.
– Lab exercises (failover and ECMP) solidify understanding.

**Expected Output:**

• A functional DHCP server on FortiGate.
• Verified static and dynamic routing tables.
• Properly configured ECMP for traffic distribution.
• Secure RPF-enabled interfaces.

(Note: Telegram/WhatsApp URLs and unrelated comments were removed as per instructions.)

References:

Reported By: Tasirdad Fortigate – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅

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