How to configure DHCP option 114 on Windows DHCP server
Overview
IETF RFC-8910 defines a standardized method for networks to notify clients of the presence of a captive portal. This is accomplish via a special DHCP option (114) which points clients to an RFC-8908-compliant "Captive Portal API" endpoint via which clients can request their "captive" status, and if captive, discover to what URL a browser window should be opened. Taking advantage of this captive portal detection method can make the captive portal experience smoother for end-users on compatible devices.
MetaDefender NAC 8.2.0 and later exposes a RFC-8908-compliant API endpoint to which DHCP option 114 can be pointed: https://portal.myweblogon.com:8443/captive-portal/api.
To implement this functionality on Windows Server 2019 and later, follow the instructions below.
How to configure DHCP option 114 on Windows Server
- On the server running DHCP, open the DHCP MMC.
- Expand DHCP and select DHCP server name.
- Right click IPv4 or IPv6, select "Set Predefined Options"
- In Predefined Options and Values window, click Add.
- Then in Option Type window please insert the information as below:
Name: 114 Captive Portal URL
Data Type: String
Code: 114
- Click OK, this option has been added on the DHCP server and you can configure this option on specific scope.
String value: https://portal.myweblogon.com:8443/captive-portal/api
