My questions:
As I understand, using a VPN router and dialing into my no-ip network address from my android, this is what happens: The no-ip address would be https:// xxxx.ddns.net ?
Yes No
You'll access your public IP. The DDNS service used is optional but just makes that easier. But basically, yes, you'd set up that host name in whatever VPN client you use (see below).
Dialed from an unsecure WIFI network, this dialing string would not be able to be sniffed out by bad actors?
Yes No
Hopefully you're not dialing in but, no, that's a little off. The actual connection would be seen at some level since the larger network needs to know how to route traffic from one place to another. There's a way to better hide that using a public VPN that you might employ but that's kind of a different matter and not something that you probably need to consider here.
What it will do is better secure the connection between your client and your system and encrypts the information inside that data stream so that someone can't, for example, see your passwords, credit card numbers, etc. sent via that connection, can't simply pass unrequested traffic in over that port into your network, etc.
No, it does not work like this. I have to install some type of client VPN on my android which will prevent the dialing string from being sniffed.
Yes No
There are two parts - Your router will run a VPN server. You will install a VPN client on whatever device you use to access that host. Upon connection, the two will negotiate a secured connection.
I understand there are various types of VPN software that can be installed on the new ASUS RT-AC68P Wireless-AC1900. Is the one that comes with it the best one, easiest to implement? Would you recommend another?
Yes No
Unless you have some specific reason to do otherwise, then just use the stock ASUS VPN to get started. It's probably all that you'll ever need, makes it easy, and works well.
Is stunnel an additional protocol?
Yes No
Is it included in the router’s VPN software?
Yes No
What does stunnelling do and is it recommended?
Yes No
I read on this forum that some members were able to buy a refurnished router and download and install the firmware themselves. But 6 hours? How fast were others able to do this and is it really that difficult?
Stunnel is for things that don't provide for native SSL-encrypted connections. Using the VPN you most likely don't need it. Not entirely true but for most purposes here it's more something that would be used instead of VPN in certain circumstances since what's being connected doesn't have the ability to do encrypted communication on its own. Basically, it creates a secure wrapper around the normal traffic to/from that device/program. You don't need to deal with it at all just to set up a VPN into your network.