If it is inside the linuxmce Net you should open port on the core
go to webadmin Advanced > Firewall rules And create a rule there for it
on your router you should open the port for the linuxmce Core not for the actual NAS
Hope it helps
Good Luck
Cesar
Actually it depends on a number of things - FTP for a start off can be a pain across NATs and firewalls depending on whether it is passive or active. And the advice above will only work in certain circumstances - there are other ways of doing this. If this is still an issue, let me know and I will try to help.