Accessing older iDRAC virtual consoles on MacOS

I recently inherited some 2012-era Dell servers for development purposes. I wanted to use remote console to reinstall the OS, but ran into two problems:

Problem #1 - “Launch console” downloads an unclickable shortcut

In Chrome, when you click the link to launch a virtual console, Chrome downloads a file (which can’t be double-clicked to launch) named something like:

viewer.jnlp(192.168.1.2@0@batman1,+PowerEdge+R320,+User-+root@150365966088@ST1=791985e23931d5d86bba90b525bc6441)

I found a Chrome extension which turns these downloads links into launchable .jnlp files, like:

viewer(1192.168.1.2@0@batman1,+PowerEdge+R320,+User-+root@1503659646088@ST1=791985e23931d5d86bba90b525bc6441).jnlp

Problem #2 - New java doesn’t trust old java

Turns out, if your iDrac version is too old, the .jar for the remote console is signed with MD5, and Java >= 8u131 treats it as unsigned (and so refuses to run it).

I ended up with this error:

Unsigned application requesting unrestricted access to system. The following resource is signed with a weak signature algorithm MD5withRSA and is treated as unsigned.

I found a helpful article re the cause, which presented a quick workaround:

On MacOS El Capitan, edit /Library/Internet\ Plug-Ins/JavaAppletPlugin.plugin/Contents/Home/lib/security/java.security, so run:

sudo vi /Library/Internet\ Plug-Ins/JavaAppletPlugin.plugin\
/Contents/Home/lib/security/java.security +613

And change:

jdk.jar.disabledAlgorithms=MD2, MD5, RSA keySize < 1024

To:

#jdk.jar.disabledAlgorithms=MD2, MD5, RSA keySize < 1024

Reload the .jnlp, and it should successfully launch.