Time Capsule Port Forwarding failure

I am using Time Capsule together with Qnap TS-269H.

I already set below things:
- Airport Utility => Port Forwarding for TCP/UDP 6881-6999 for (which is IP of my NAS)
- NAS => port 6881-6999 are used for BT

But still BT is slow.  When I used tool to scan these ports they are still closed (if port forwarding is successful then they should be open).   

Can anyone help?

push.  Any advice?


我也是用time capulse 同269H
沒有用任何port forwarding
BT 都OK, 唔慢.
試下upnp setting.