I don't know whether there is a single command to get all iDRAC IP. You can run below command for each server to get iDRAC IP racadm getniccfg [-m ]  E.g. racadm getniccfg -m server-1
I can easily set iDRAC IPs with "racadm deploy". But is there some way to list (or figure out) the IPs of all iDRACs of the inserted blades?  
M1000e: how to get iDRAC IPs from cmc console