Ethernet Adaptor (en2) and (en3)-What are they?

I'm going to guess that you are running Parallels? (If not I have no idea)

If you are they are basically clones of your Ethernet port. En3 is the port windows sees and uses, and En2 is a bridge between that port and the physical port in your computer that OS X uses.

Interesting side effect of it is that Parallels doesn't use the same MAC address as OS X. So if for some reason you MAC is blocked on a network, you can still access the same net work if you boot windows in Parallels. I've been on bandwidth restricted networks and had my MAC address locked before and switching to windows in Parallels always give me access back. Its also kind of amusing because each boot or parallels gives you a new MAC address.