I also install the elasticsearch in my job computer,it is the Windows 7 System and this elasticsearch has no plugins.
I use my java project to connect to this elasticsearch in my eclipse ，and I can get the data what i push in the elasticsearch .
then I put this project in the outside network，when it connect，the waring is appearenced:"WARN ---- [elasticsearch[client][management][T#1]] io.netty.util.internal.MacAddressUtil: Failed to find a usable hardware address from the network interfaces; using random bytes: 04:79:6e:6e:06:4c:3f:d9", I check the logs ,it dose not has a useful message for this connect.