This equipment is not fully “stealthful” inasmuch as it did respond to our probing. I ran a Universal Plug n’Play (UPnP) Internet Exposure Test using the grc.com site you mentioned and got:

Using direct connect, you can, if done right, keep things in what you called “stealth mode”. As long as most of your network devices have ICMP pings deactivated (which most are by default these days) then anyone trying to hack their way into your network won’t be able to figure out which ports are open using a port scan. Less tech people will be able to easily use WD’s M圜loud. That would make it very user friendly and give it good reviews. IMO, WD best approach is to do something like how Google Drive works. Of course hackers could attack WD but they should be monitoring this more then I do. When I’m using the relay mode, all ports are “Stealth” as I check them with ShieldsUp at My home network is invisible on the internet unless I connect to a server. Hacker can see it on the internet even when the ports are closed. What I don’t like about the direct connect is that some ports are no longer in “Stealth” mode. I also beleave all files transfers are using SSL.

This must be the problem WD has reported and they have not reported fixed yet. I’ve notice in the dashboard the rely is sometimes up, sometimes down without me doing anything. I’m kind of worn out trying all the different things.

Using ftp via browser