Netplay is a very complex system, I've said this time and time again in threads and its getting really, really old repeating myself. To make anything work using Netplay or any other online system you need a lot of scripting experience, more so if you want it to work like an actual ORPG, with server side saving and such. If you don't know coding or have anybody willing to help you with coding don't bother trying a Netplay project. Its as simple as that.
As I just said in another thread, I have no idea about 2.1.7 but I know that by default 2.0 which 2.1.7 is based has saving aslong as the server isn't restarted, to get it to keep files would require a large amount of work.