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conu-iancu
conu-iancu
New Member
April 18, 2025
Question

Fortigate routing 2 public IP spaces

  • April 18, 2025
  • 1 reply
  • 739 views

I've received IP address information from my new ISP, and it looks like I may need an additional router. They provided two public IP ranges: one labeled as the WAN, which is a /30 subnet, and another labeled as LAN, which is a /29 subnet.

From what I understand, the /29 subnet contains my usable public IP addresses, and I need to route traffic from this range through the WAN (/30) subnet.

Is it possible to configure this setup using a FortiGate firewall, while still using it as a traditional firewall—publishing services from an internal or DMZ network through the /29 public IPs? What would be the best way to approach this configuration?

1 reply

Toshi_Esumi
SuperUser
Toshi_Esumi
SuperUser
April 18, 2025

Yes, that's a very common way to provide an additional /29 subnet by any ISPs. The IP in the /30 subnet is for your WAN interface IP, while their GW device takes the other IP in two available IPs within the /30. Then you can use the /29 for your LAN side interface, or DMZ interface as you wish. Of course the FGT's DMZ interface needs to take one IP from the /29, then all devices in DMZ can use one of 5 available IPs.

 

Toshi

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