3394 is the Microsoft RDP port....NEVER leave that open.
With the way that NAT works, anything from INSIDE your network initiating a connection will be an open outgoing port. that doesnt do anything for you in this case.
are you trying to connect to your PUBLIC ip from within the network?
if server 192.168.1.250 is serving http on port 80, thats internal. when you are internal on the network, you dont need to specify port
if you have a PORT FORWARD of 8080 on the outside, going to port 80 on server 192.168.1.250, then when you are OUTSIDE the actual network (NOT trying to access your public IP from inside the LAN) you would just punch in your public ip/domain name and append port 8080 to it.
http://myfakedomain.com:8080
if you have things set up correctly, it will just take that request and redirect you to port 80 on the internal server.
i dont think you quite get a grasp on networking here. this isnt an issue with FreeNAS, but an issue with your networking.
I am trying to understand something. You say you have a VPN set up on your router. How do you use the VPN? Is it OPENVPN, PPTP, or IPSEC?
Honestly, you should NOT be forwarding your FREENAS GUI to the outside world, you are asking to have your entire NAS trashed.
Based on what info you have provided so far, suffice it to say, you probably shouldnt be forwarding anything to the outside world, and instead be using VPN, otherwise you are asking for trouble. If you dont understand NAT, Firewalls, Port Forwarding and basic security, you shouldnt put your NAS out in the public.