That depends on the protocols used to manage. If using WMI, then yeah (or if you need AD authentication). You could create an 'instrumentation account' at these locations. Or can you just use the iDrac which has it's own network? Or just SNMP? So there are different options and you will likely have to test out a few different protocols to get the solution that will work best for you.
3Mbps might be too slow. If you dial back discovery, inventory, you might be ok. But you won't be able to push system updates (fw/bios) over a WAN.
Rob
ps. some whitepapers on www.delltechcenter.com/ome ...maybe one of these or another one...