Instead the service providers will use non-routable (private) addresses (see here for details) internally, then NAT them to a small range of routable addresses.
So it's like being on Wifi and the service provider is like the router?
So it's like being on Wifi and the service provider is like the router?
Yes, exactly the same. And if you set up a wired network at home, you'll usually use a private address range as well (as will most small companies, and even many larger ones). The router/gateway then has a single externally routable address and NATs all the outgoing traffic. If you have control of the router then you can add port forwarding, but otherwise all you can do is use some sort of external "reflector" - both the client and server connect to an external system and that manages routing the connections between them. There are setups for doing this with VNC, but I've not looked into what's available (or what they cost) as I can currently connect to my home network directly.
JonWW - asuming you are wanting your remote party to initiate a connection to your n900 while you have presenceVnc listening for an incoming connection ... it's true that in UK you'll not be able to do that on a cellular data connection, for the reasons stated by Rob1n.
But surely you can just connect into the remote client using presencevnc in that stuation anyway? If for some reason you really need the remote party to initiate the connection then, as the previous poster said, reverse SSH would be the way to go.
Assuming its a Win box you need to access, just install openSSH on the remote party's PC. You can then set up a reverse SSH tunnel to the remote machine from your n900 such that the remote party can still do what you want (pull up their tightVNC from tray and enter an IP to connect to you) - but the IP they enter will now be localhost:xxxx (where xxxx is an arbitrary free port you used when setting up the tunnel, and which the tunnel port forwards to the port on which presencevnc is listening for connections). A fringe benefit of this is that the IP they enter will always be the same - no need for them even to type in a full address & risk typo's - as they are always connecting to the same port on their own local PC regardless of your n900's current IP address.
Obviously, you'd need to have the tunnel running all the time in your scenario or else it wouldn't be open at the arbitrary time your remote party decided to initiate a session - but as your scenario presumably already requires you to have presencevnc running on your phone all the time in order for the arbitrary connect request to succeed, I don't think this small overhead is an issue.
Making the reverse tunnel startup every time the n900 changes between wifi & cell data takes a bit of work but once done it is reliable & doesn't hog battery when the tunnel is idle. I have this exact config on my n900 (to allow me to ssh/vnc into it if it's lost/stolen or if I've left it at home etc.) - it works great for me.
HTH
.EDIT forgot to say that the new zoom bar is fantastic, just what I needed! Any chance that it could be rescaled slightly to allow for easier fine control when enlarging an area? Currently (at least when controlling a PC set at 800x600 res) the initial "full screen" position of the slider bar is about 80% or so ... I personally can't think why I'd ever need to zoom out from the initial full screen dispaly, I'd only want to zoom in - so the more towards 0% the slider starts at, the easier it would be to set a comfortable zoom level. I'd stress though that it's very useable "as is", just wanted to give some feedback as I really appreciate your work.
Rob1n
My home network is not the problem, I can get through that ok as my router has port forwarding, it's others who require help when I am out and about and I cannot access them because their routers don't have port forwarding, Sky routers for example.
Pigro
Interesting reading, something I will have to have a play with. It does, at first glance, seem complicated to setup, too much for someone over the phone with limited computer skills to do, especially when I have yet to learn myself. I have OpenSSH server and client on the phone and use it all the time to access the phone from my PC. I shall explore more, thanks.
ah, I see better what you're after now. Agreed that the ssh stuff is somewhat complex for you to set up initially. You'd need to install & configure openSSH on his PC (and you'd need to get your head aound security, eg. public key auth etc.) but once in place it is totally transparent to both you and your friend behind the sky router. He simply has to enter localhost:xxxx into the vncserver tray app after you start your presenceVNC client in listening mode and it should "just work" (albeit rather slowly if you are on 2G). It's probably overkill however unless it's on behalf of someone who you need to support very regularly and/or who provides "favours" in return :-)
is there an easy way to return to 1:1 zoom? I'd like to not burden the CPU with unnecessary scaling. Screen updates are sometimes slower than with the other VNC client & I wonder if the scaling is the cause.
Fantastic app though, it's so nice to finally be able to type lower case in a VNC client. Great stuff.
is there an easy way to return to 1:1 zoom? I'd like to not burden the CPU with unnecessary scaling. Screen updates are sometimes slower than with the other VNC client & I wonder if the scaling is the cause.
Not yet, but I'll add something like doubleclicking the slider for 100% zoom.
Downscaling really is very expensive (at least if you want to be able to read text), but there seems to be lots of room for improvement
