Fortigate Captive Portal not working for WIFI users but LAN Users working properly

[Omsharma03]

We are ussing Fotigate 201F- Captive Portal applied and LAN User authenticate but Wifi Users not authenticate, both Networks are different segment (LAN- 10.161.0.0/16, WIFI- 10.172.0.0/16
while applied the Captive portal, LAN Users properly authenticate but WIFI users trying to connect the the authentication but page not open however did not get dhcp IP but when disable the Captive Portal then users connect properly through DHCP IP.

Connectivity-- Users---LAN/WIFI >> L3 Switch >> Fortigate >> Internet.

[saleha]

Hi Omsharma03,

Thank you for reaching out. I have seen a case in the past where computer trying to authenticate through captive portal for wireless would try to troute the authentication request using wired adapter. The condition was both wired and wireless network adapters were connected at the same time. Does this issue happen only when the wired adapter is connected to the network at the same time you are trying to connect to wireless please? If this is the case try wireless while ethernet port is unplugged on the device. Otherwise, First troubleshooting step is to run a sniffer or packet capture on the fortigate and wireshark on the connecting device to simultaneously to monitor traffic when the problem happens:

- sniffer:

# diag sniffer packet any "host x.x.x.x" 4 0 l ----- sniffer output will not show payload of the packet

- packet capture can be created by going to "Network>Diagnostics" or "Network>packet capture" depending on the version of the fortios running.

Thank you,

saleha

[Ashishdeep]

Please follow this video Captive Portal configuration on Fortigate Firewall (youtube.com)

Customize FortiGate Captive Portal - Wireless (youtube.com)

How to troubleshoot if captive portal not... - Fortinet Community