I have a Dell R620 server, with an iDRAC7 Enterprise license. The "DNS DRAC Name" is set to "idrac-NNXXXXN", where "NNXXXXN" is the service tag of the machine. Every time I type something new into that field (In the web administration page, "Overview -> iDRAC Settings -> Network") and click on "Apply", the page refreshes after a few seconds, with the field changed back to its original setting. I have tried several different names, including some short and simple names, just in case there's a problem with the name, but the behavior is the same no matter what I type there.
I've done the exact same thing on other very similar servers (including another R620 with an iDRAC7), and it works on all of the others. I have tried clicking "Reset iDRAC" (which I presume reboots the instance of Linux running on the iDRAC), and that has no effect. Not that I expected it to, but it was worth a try.
Any suggestions? Am I doing something obviously wrong?