Chapter 9. HTTP header authentication

Guacamole supports delegating authentication to an arbitrary external service, relying on the presence of an HTTP header which contains the username of the authenticated user. This authentication method must be layered on top of some other authentication extension, such as those available from the main project website, in order to provide access to actual connections.


All external requests must be properly sanitized if this extension is used. The chosen HTTP header must be stripped from untrusted requests, such that the authentication service is the only possible source of that header. If such sanitization is not performed, it will be trivial for malicious users to add this header manually, and thus gain unrestricted access.

Downloading the HTTP header authentication extension

The HTTP header authentication extension is available separately from the main guacamole.war. The link for this and all other officially-supported and compatible extensions for a particular version of Guacamole are provided on the release notes for that version. You can find the release notes for current versions of Guacamole here:

The HTTP header authentication extension is packaged as a .tar.gz file containing only the extension itself, guacamole-auth-header-0.9.14.jar, which must ultimately be placed in GUACAMOLE_HOME/extensions.

Installing HTTP header authentication

Guacamole extensions are self-contained .jar files which are located within the GUACAMOLE_HOME/extensions directory. If you are unsure where GUACAMOLE_HOME is located on your system, please consult Chapter 5, Configuring Guacamole before proceeding.

To install the HTTP header authentication extension, you must:

  1. Create the GUACAMOLE_HOME/extensions directory, if it does not already exist.

  2. Copy guacamole-auth-header-0.9.14.jar within GUACAMOLE_HOME/extensions.

  3. Configure Guacamole to use HTTP header authentication, as described below.

Configuring Guacamole for HTTP header authentication

The HTTP header authentication extension provides only one configuration property, and it is optional. By default, the extension will pull the username of the authenticated user from the REMOTE_USER header, if present. If your authentication system uses a different HTTP header, you will need to override this by specifying the http-auth-header property within


The HTTP header containing the username of the authenticated user. This property is optional. If not specified, REMOTE_USER will be used by default.

Completing the installation

Guacamole will only reread and load newly-installed extensions during startup, so your servlet container will need to be restarted before HTTP header authentication can be used. Doing this will disconnect all active users, so be sure that it is safe to do so prior to attempting installation. When ready, restart your servlet container and give the new authentication a try.