I am experiencing problems with forwarding port 445 on my DIR655.
I want to use the forward on 445 for an ipad app 'filebrowser'. Filebrowser uses port 445 for access.
I want to acces my Synology DS109 NAS with the filebrowser app on my ipad.
The help PDF of filebrowser states:
Port Forwarding
Firstly, note that you can only configure a firewall in this way to connect to one computer on your network for example. You won’t be able to access your Desktop computer and a NAS at the same time for example.
Also note that each device on your network has its own IP address. You will need to use these during the setup.
Here are the setup steps:
1) Find out the IP address of your target machine as it appears on your home network.
On a PC: Use a Command Prompt (from Accessories), type ipconfig and look for the IP or IPv4 address in the output.
On a Mac: Click the Apple logo, select System Preferences then Network. Your IP address is shown on the next window.
On a NAS: The IP address will probably be shown on its status or configuration web page.
2) Log onto your router’s configuration page and locate the Port Forwarding screen. This may also be called Firewall Rules or Inbound Services.
3) Create a new firewall rule to send SMB traffic on TCP port 445 to your target machine’s IP address. If you can’t find SMB or enter port 445, you may need to create a service first using a different menu. This screen shows the rule being set up:
(PDF: http://www.stratospherix.com/products/guides/SetupForExternalAccess.pdf page 4)
LAN-wise, i have no trouble accessing my NAS with filebrowser (or with any other programm or app).
I also dont experience any problems with other forwards. I have these port forwards / virtual servers running:

Accessing my NAS over internet on port 5000 is no problem, also accessing sabnzb+ on 9200, no problems there. FTP on port 21 is no problem, only accessing port 445, it does not work.
Can someone please advice?