As with any installation of new hardware we should check the support website to make sure we have the latest firmware and software available.
After logging into the Dell support website there was a new update available for the DR4100 device I was installing. The patch was downloaded and the system was upgraded. The screen warns this can take a long time. After the update I rebooted the unit, unfortunately the unit was then unreachable from the LAN, I was able to gain access via the iDRAC interface.
Looking though the logs I could see that while the software had updated the firmware packages built in to the update bundle had not. This can happen if the iDRAC has started up too quickly.
The solution is to open the iDRAC console, login to the DR4100 with the 'administrator' user account and password and issue this command.
maintenance --remote_access --racreset
After the iDRAC reboots, login to the console again and start the firmware manually.
Enter the 'administrators' password and wait for the firmware to complete. After approximately 30 minutes the update should complete and ask for the restart.
Once the reboot has completed you should be able to access the web interface.