nestopia im not know if virutanes or punes have also fceux
im more recomend fceu mm for better mapper suport but im dont know thats option in fceu mm for nestopia servers are open often there was nes thread nes gameplay online and roms list but you find with search
game can be also hosted mean you can server but you have forwarded ip a.k.a external ip my pc and every one who have pc cant make a server becuse dont have this ip its can be unlocked but im think you must have tool for that router or something and ask about it your net provider
im dont have it so im cant you can also use openvpn or other services to make server or try with hamatachi
https://www.vpn.net
Create virtual private networks on-demand
LogMeIn Hamachi is a hosted VPN service that lets you securely extend LAN-like networks
to distributed teams, mobile workers and your gamer friends alike. In minutes
but im think you will have pay for that
im will try an tell you its works or not im hope its free
im find info
Hamachi is free for up to 5 computers in your network.
so its free if you not make more than 5 when you do so you must pay