Troubleshooting Origin Server Compression


The purpose of this procedure is to troubleshoot issues compressing content on a customer origin server.

Related Topic

Accept-Encoding Request Header

Compression may only be applied to requests that include an Accept-Encoding header. This request header must be set to a format (e.g., gzip, deflate, or bzip2) supported by your web server.


Verify that the request includes the Accept-Encoding header.

Verify that the Accept-Encoding header is set to a supported format.

IIS Web Server Only

An IIS server will not compress requests that contain a Via header. This issue can be resolved by either:

  • Disabling this behavior on the IIS server.
  • Setting up Rules Engine to strip the Via header from the request proxied to the origin server. This configuration may be achieved by creating the following rule:

    • Match: It should match requests to any customer origin server that points to an IIS server.
    • Feature: It should contain the Proxy Special Headers feature. Make sure that the value assigned to this feature does not contain "via."
      Sample value:
      x-forwarded-proto x-host x-midgress

Additional Information

The Via request header indicates that a user's request is being proxied through our network to the origin server (e.g., IIS server). By default, an IIS server will not serve compressed content for proxied requests, since it assumes that a proxy server cannot handle compressed content.


Verify that requests do not include the Via request header.