WX3840X Local portal web server can not pop up the portal page automatically

Fit AP(WA6636) + AC(WX3840X) + Radius server(third party) + DNS server (third party)

Wireless client : smart phones (Android and IOS)

The customer uses WX3840X for wireless local portal authentication. 

WX3840X provides portal web pages, and AAA authentication is performed on a third-party RADIUS server. 

But the problem is that after the client connects to WiFi, the portal web page does not automatically pop up, but it can be opened by entering the specific URL.

Usually, the reason why the portal web page cannot pop up automatically is that there is no free-rule configured for DNS.

After the wireless client connects to wifi, it will automatically send network sniffing packets, and this process requires the DNS server to resolve the address for it.

We checked the environment of customer, we found out that this is the free-rule for DNS.

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portal free-rule 1 description ip any tcp 53

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Customer configure description, it should be destination. Then we changed it, and add free-rule for UDP, too.

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portal free-rule 1 destination ip any tcp 53

portal free-rule 2 destination ip any udp 53

#

However, it still can not automatically redirect. 

We noticed that the DNS setting of the wireless client is not 8.8.8.8, the DNS server is the private server of customer.

When we modify the DNS server to 8.8.8.8, the redirect can work. Therefore, we thought the issue occurred on the internal DNS server.

Finally, we found the reason. The customer also configured Portal authentication for the wired service, and the DNS server did not pass the authentication, so it could not work properly.

When you encounter the issue of the portal page not automatically popping up: 

1. Please use the URL: http://1.2.3.4 to test if the redirection function is working properly. 

2. If the redirection is not successful, please refer to the Portal configuration manual to check the Portal web-related configurations. If the redirection is successful, please use the URL: http://google.com to test again. 

3. If the redirection still does not work at this point, please check if there is a free-rule related to DNS configuration, for example, 

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portal free-rule 1 destination ip any tcp 53

portal free-rule 2 destination ip any udp 53

#

please make sure to check for any spelling errors, such as in this case, writing "destination" as "describtion," which often occurs. 

4. If the redirection still does not work, please check your DNS settings.