The JRE package includes a
bin/javaws binary. That is the "Java Web Start", which takes the
*.jnlp file and can download and run the applet.
You just need to make sure the
javaws of an appropriate version of Java is associated with
*.jnlp files (MIME type
application/x-java-jnlp-file) in your browser and/or desktop environment, and the browser will be able to use the
javaws binary to "open" the JNLP file.
The only practical difference might be that the ILO console UI opens in a separate window, rather than being embedded into the browser's window using an old and vulnerable browser plugin API designed for Netscape Navigator browser back in the 1990s.
If you use self-signed certificates for your ILO remote consoles, you may also have to set up a security exception to trust the certificate both in the web browser and in the JRE. The latter can be done using the Java Control Panel, which is available as
bin/jcontrol in the JRE package.
This separation of the console client from the browser even allows you to run a 64-bit browser and still use a 32-bit Java JRE to run the console application. This turned out to be important for me, as I once had to get the "virtual CD-ROM" functionality working with a server that had a really old ILO version: the virtual CD-ROM function only worked with 32-bit Java.