HTTP - Origin (Header Field)
1 - About
user agents isolate content retrieved from different origins to prevent malicious web site operators from interfering with the operation of benign web sites.
same-origin policy - user agents allow content retrieved from one origin to interact freely with other content retrieved from that origin, but user agents restrict how that content can interact with content from another origin. implementation are application specific and are then defined in HTML and WebSockets [RFC6455].
2 - Articles Related
3 - Management
3.1 - Set
On a Apache server, the origin is defined as the
ServerName property of the configuration file