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Raz1980
Raz1980
New Member
February 18, 2026
Question

Need Help in Configuring Multiple IP's for Fortigate

  • February 18, 2026
  • 1 reply
  • 119 views

The vFSA appliance is deployed in IBM Cloud Classic (Dallas) in an active–passive configuration with only one public subnet IP currently assigned, and no additional public IPs available in the subnet.

 

We have five web servers hosting different websites that must be externally accessible. In the absence of spare public IP addresses, we would like guidance on how to expose these services behind the firewall with separate public IPs.

 

Please advise on the recommended architecture or configuration for this setup. If possible please share some links if there are any.

 

Thanks

    1 reply

    esalija
    Staff
    esalija
    Staff
    February 20, 2026

    Hi @Raz1980 ,

    - To expose multiple web servers behind a FortiGate firewall with a single public IP address, you can use Virtual IPs (VIPs) with port forwarding.
    - This allows you to map different external ports to the internal IP addresses and ports of your web servers.
    - Use a single public IP address and configure Virtual IPs (VIPs) to forward different external ports to the respective internal web servers.
    - For example, map external ports 8080, 8081, 8082, etc., to the internal port 80 of each web server.

    - Create Virtual IPs:
    - Navigate to Policy & Objects > Virtual IPs.
    - Click Create New and select Virtual IP.
    - For each web server, configure a VIP with:
    External IP Address/Range: Your single public IP.
    Mapped IP Address/Range: The internal IP of the web server.
    Enable Port Forwarding: Map an external service port to the internal port (e.g., external port 8080 to internal port 80).

    - Create firewall policies to allow traffic from the external interface to the internal interface using the configured VIPs.
    Example Configuration
    Web Server 1:

    External Port: 8080
    Internal IP: 192.168.1.1
    Internal Port: 80
    Web Server 2:

    External Port: 8081
    Internal IP: 192.168.1.2
    Internal Port: 80
    Web Server 3:

    External Port: 8082
    Internal IP: 192.168.1.3
    Internal Port: 80

    https://community.fortinet.com/t5/FortiGate/Technical-Tip-Assign-multiple-public-IP-addresses-to-FortiGate/ta-p/199844
    https://community.fortinet.com/t5/FortiGate/Troubleshooting-Tip-Internet-connection-fails-when-Fortigate-VMs/ta-p/244293
    https://community.fortinet.com/t5/FortiGate/Technical-Tip-Setting-up-a-VIP-load-balance-with-HTTP-host-check/ta-p/198274

    Best regards,
    Erlin

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