The DRAC5 is an old remote access card, found on servers such as the PowerEdge 300, 2950, 1950 etc. I have one built in about 2007.
Trying to use it today with modern browsers and JREs will lead to errors, mainly due to added security improvements/checks which have been implemented since then.
Fortunately, there are workarounds for these errors. A rather detailed page can be found here (thanks Paul) https://paulschreiber.com/blog/2018/01/27/using-a-dell-drac5-with-a-modern-browser-and-os/
This page suggests to issue a new certificate and to lower the security requirements of the JRE in use. A much interesting work, but the procedure is fairly boring and error-prone. I thought that it would be rather simple to bring up a legacy version of Firefox Portable, together with a likewise aged portable JRE.
So I took FirefoxPortable_3.5.11_English.paf.exe from here https://sourceforge.net/projects/portableapps/files/Mozilla%20Firefox%2C%20Portable%20Ed./ and Java_Portable_6_Update_22_online.paf.exe from here https://sourceforge.net/projects/portableapps/files/Java%20Portable/ . Other seasoned versions will likely work.
I “installed” them in a temp dir. Firefox went in FirefoxPortable\ and jPortable in CommonFiles\Java\ . The only thing to keep in mind is that when you launch the remote console, a file named vkvm.jnlp is downloaded. Do not save it to your hard drive but instead choose to open it with CommonFiles\Java\bin\javaws.exe, the Java Web Start interpreter. Then simply accept when asked if you want to run the application and consider it trusty.