Operating System (OS) Adoption

Last updated: December 17, 2025

Intricately has visibility into which Operating System (OS) an application runs on by inspecting the OS signatures leaked via HTTP response "Server" headers. 

While there are more robust (and complex) ways of identifying OS deployments, Server headers are a simple way to get visibility into which types of OS a company uses.

The reasons why relying on the Server header is not optimal are:

  1. Server headers are only returned by web servers so other hosts or server types such as authentication gateways, mail servers, and others will not have them.
  2. Server headers are easy to manipulate and security-minded administrators will strip out OS-identifiable information from them.
  3. Server headers won't always contain OS identifiable information.

The following are examples of Server headers and the OS distribution they map to:

Server Header OS Type
Google Frontend Unknown
Apache/2.2.3 (CentOS) Cent OS
Microsoft-IIS/8.5 Windows
Apache Unknown
akamai/nginx Unknown
Apache/2.4.46 (Unix) Unix