Firstly, are you sure you have public IP assigned by your ISP?
Secondly, if you do have public IP, you should add some port-forwarding rules for your server in your router settings, so router knows that when packet goes to port i.e. 64087 it should route it to your notebook, i.e. 192.168.1.2
I think this thread could be of use to you https://crymp.net/forum/thread.php?id=53&page=last&lu=1423764364
There is no NAT negotiation from side of master and won't be in future, reason for this NAT negotation works for some group of people, but also doesn't work for another group of people and those people would be discriminated, so it's better if either everybody can connect or nobody can connect.
Sadly, trends at ISPs today are that more and more people have symmetric-NAT, which means group of people who wouldn't be able to connect is getting larger every day.
Go to router settings, find something like "Forwarding", go to "Port forwarding", add new, port: your server port, IP address: your device IP on WLAN (use ipconfig in command prompt to find that one out)