> For the complete documentation index, see [llms.txt](https://docs.console.zenlayer.com/welcome/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.console.zenlayer.com/welcome/content-delivery-network/domain-management/cdn-settings/back-to-origin-settings.md).

# Back-to-origin Settings

Set the upstream protocol, enable WebSocket, and set origin host header.

<div align="left"><figure><img src="/files/Ve4FCw1aLSlPI3PWVDfO" alt="" width="383"><figcaption></figcaption></figure></div>

* Upstream Protocol
  * Set Upstream protocol to HTTP: Requests are redirected to the origin server over HTTP with the port you defined.
  * Set Upstream protocol to HTTPS: Requests are redirected to the origin server over HTTPS with the port you defined.
* WebSocket\
  A TCP-based protocol that is useful when you need long-lived bidirectional connections between clients and servers. A persistent connection is often a requirement with real-time applications. The scenarios in which you might use WebSocket include social chat platforms, online collaboration workspaces, multi-player gaming, and services that provide real-time data feeds like financial trading platforms. Data over a WebSocket connection can flow in both directions for full-duplex communication.
* Back to Origin Host\
  Different back-to-origin HOST header can be configured to access one of targeted origins for the same accelerated domain name.