We have a Poweredge R510 with iDRAC6 Enterprise v2.90 which we can no longer connect to using the virtual console. This issue started when the motherboard was replaced due to a faulty temperature sensor.
I am using the same method of connecting as I was before - using javaws on Fedora 27. I have also tried using a Windows machine with the same result. The error I get is "Connection Failed". I have tried clearing cache, reinstalling java, and enabling SSLv3 etc.
I'm pretty sure this isn't a client side issue as this was working fine before the motherboard replacement.
Did you move the idrac enterprise license from the old system board to the new board?
It is part of this board, was it moved to the new system board? http://downloads.dell.com/manuals/all-products/esuprt_ser_stor_net/esuprt_poweredge/poweredge-r510_o... Page 135
Just for anyone else with this problem.. To get this to work I had to downgrade java to version 7u51 from http://www.oracle.com/technetwork/java/javase/downloads/java-archive-downloads-javase7-521261.html and also set the security level to medium.
I'm not sure why a motherboard replacement would have required this but it is working now.