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uniquewaheed
uniquewaheed
August 14, 2026
Question

Remote Access VPN using DSL Modem Public IP

  • August 14, 2026
  • 1 reply
  • 51 views

 

Hi All , 

Am using the following network and wanted to implement Remote Access VPN over Fortinet60F using public IP available on Wifi DSL modem. 

What would be the preferred method to deploy Firewall Transparent or routed mode. as per my knowledge am not able to implement RA VPN using transparent mode. Right ?

Secondly if am not using DHCP on DSL modem can I assigned IP from Fortinet LAN Interface DHCP service and WIFI authentication from DSL modem for connectivty purposes. Or any better idea to do it. 

Thanks in advance for tips and ticks

regards

 

 

 

 

 

 

1 reply

farhanahmed
Staff
farhanahmed
Staff
August 14, 2026

Routed/NAT mode is recommended. Ideally, place the DSL modem in bridge/passthrough mode so the public IP is assigned directly to the FortiGate WAN interface.

If bridge mode is unavailable, assign the FortiGate WAN a private static IP and forward UDP ports 500 and 4500 from the modem for IPsec VPN. Also confirm the ISP is not using CGNAT.

Wi-Fi clients connected to the DSL modem cannot normally receive DHCP from the FortiGate LAN and would bypass FortiGate inspection. For better control, connect a separate AP behind the FortiGate and use the FortiGate as the DHCP server.

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