Overview
The custom header can carry the geographical location information of the client IP to the origin.
Note
The country/region value is represented by an ISO 3166-1 alpha-2 code (a two-letter country/region code).
Currently, IPv6 is not supported.
Instructions
1. Log in to the EdgeOne console and select Site Acceleration > Network Optimization from the left sidebar.
2. On the Network Optimization page, select the desired site and click 
3. In the pop-up window, you can customize the header name or use the default name "EO-Client-IPCountry". Click Save to apply the changes.