---
title: Fastly-Client
summary: null
url: https://www.fastly.com/documentation/reference/http/http-headers/Fastly-Client
---

This header is attached to all requests that come from a Fastly server.  In practice, this means that in any service that has [clustering](https://www.fastly.com/documentation/guides/vcl/clustering/) or [shielding](https://www.fastly.com/documentation/guides/concepts/shielding/) enabled, `Fastly-Client` will be true on all but the first server that received the request.  It will also be included on the request forwarded to the backend.