Why is my VLAN captive portal redirected to the root port?

Question

I had a working XG set up with Port 2 = 172.16.16.16 (LAN Zone) and Port 3 = 172.16.17.16 (PublicLAN Zone) 
 I decided to use a Smart switch and use VLANs to seperate LAN Zone from PublicLAN Zone. The Switch would use Trunk port with VLAN ID 10 and 20 connected to Port 2 on the XG device... 
 I set up the switch and then proceeded to change the XG setup to match my VLANS : 
 Vlan ID 10 = 172.16.16.16 
 Vlan ID 20 = 172.16.17.16 
 I found I had to have an ip address on Port 2 so I added 172.16.19.16 
 The PublicLAN (with Vlan ID 20) has a HotSpot configuration (Terms and conditions) and this works. The user is redirected to a page located at 172.16.17.16 and that is expected. 
 However, the Private LAN (with Vlan ID 10) has a captive portal where username and password is required. The user is redirected to a page located at 172.16.19.16??? What is going on??? It should redirect to a page at 172.16.16.16.... By the way I can access the page at 172.16.16.16:8090/httpclient.html if I access it directly. The redirection is broken. 
 How do I fix it? 
 Device XG105 (SFOS 16.01.1)

Aditya Patel · Answer

HI MurrayCarte, 
 As you have configured the VLAN as a Hostspot , it would operate differently as a Captive portal . As per our device behavior, the captive portal for unauthenticated traffic will show an interface address instead of VLAN address on the XG appliance. There is no misconfiguration done here. If you use the manual address of the VLAN you will also get the captive portal.