ftp port forwarding on d-link DNS-320L

[#1]

hi i just installed an nas on my home network the DNS-320L working great i just can't seem to get the ftp server to run from out side my house i have an static ip so my ip dose not change i have set up the port forward in the Plusnet router see the image below for how i set it up i can't connect to it with in my home network ever via ftp yet when i turn on DMZ to the NAS only people outside can use the FTP any ideas what i am doing wrong and why its not working ? i have the Plusnet router firewall set to Defaults  

[#2]

It has to be asked you have enabled this service (FTP) on the NAS?

[#3]

yer but when i turn on dmz people from out side can see it but of course i dont want dmz left on 

[#4]

You're confusing me now, which, to be fair can easily be done, so what are your expectations? If you disable the DMZ then no one can access the FTP service so why port forward in the first place if you don't want the DMZ on?

[#5]

yer that is right i did not have DMZ on before I set up the port forward in my router to test and outside can get to the FTP on the nas but as soon as i turn DMZ off in the router and to the NAS FTP stops working 

I set up FTP port forwarding like i showed in the image in my first post but it only seems to work outside if I have DMZ on which, of course, is not really that safe i thought i would try dmz and it worked so i not sure ?

[#6]

Could be wrong but I believe DMZ opens all protocols to the outside world including FTP.

You don't want that, you just want FTP open.

I don't have access to that particular router so can't help...sorry.

[#7]

i just want port 21 open which is FTP on the NAS has set i have router Plusnet gives you for normal asdl Broadband 

[#8]

I don't use that router either, but aren't you able to simply port forward the port(s) you need to the NAS' IP without enabling the DMZ? If this can be done (someone will more than likely give you instruction on this later) you're sorted, however, if this can't be done then it's a new router, one that will allow this configuration.

[#9]

FTP requires two ports unless the router is smart enough to do FTP inspection.  In active FTP, port 21 is the control port and should let you log in but you will find you are unable to transfer files or get directory listings unless you also forward port 20 (the ftp data port).  With passive FTP (PASV), 21 is still the control port but the data ports are dynamic.  You set them on the FTP server and then you will need to forward these ports on your router as well.

Have a look here for more detail:

http://stackoverflow.com/questions/1699145/what-is-the-difference-between-active-and-passive-ftp