Lately with iDRAC 6 upgrades (I've noticed with 1.92 so far), the DRAC seems to reset itself to the default NIC selection, making it seem that the DRAC falls offline. I've had to look for this on twice now, it's not under racadm setniccfg like you'd think. You can set it with the intuitive:

racadm config -g cfgLanNetworking -o cfgNicSelection 2