Can I use VNC client with VNC Server on HughesNet target host PC?

[DSperber]

Brand new HughesNet service install just last Friday for a friend at a new home in Florida.  Latest and greatest highest-speed option, which I assume is Gen5 equipment (HT2000 Wifi modem/router).  Seems to work ok (upload appears to be 2-3Mb/s, with highly erratic download between 2Mb/s and 45Mb/s but mostly in the 20Mb/s range) given that she has no other internet service options where she lives.

Being her "IT guy", I support her remotely from my location in LA.  I prefer to use VNC software and a direct connection (using port forwarding in her router), but will fall back to Team Viewer if necessary (since it is Cloud-based and doesn't depend on router configuration).

I have been unable to connect to her PC in Florida through VNC, even though I'm positive I have configured her router's "port mapping" correctly.  I have no problem (other than slow performance) going to her PC via Team Viewer, but cannot connect at all to the host software running on her PC.  The self-test connection diagnostic in the host server software also cannot connect at all to "home base", so this seems to point to something either in the router's configuration or in HughesNet in general which is simply preventing this type of connection.

I've talked to tech support at HughesNet and they insist "all ports are open", and that the particual port being used by VNC is not specifically being blocked.  I've talked to tech support at VNC and they feel there should be no reason their connection would be failing, even in light of the very hight latency implicit in satellite connections.

So maybe there's something else I need to do in the router (since this is my first contact with it).  I've simply enabled the specific port forwarding to the IP address of the specific host PC on the LAN, and checked the "enable" box.  I've also entered that PC's MAC address in the "DHCP reservation" list, just to prevent it from moving around across machine re-boots, and to keep this port forwarding setup legitimate.

So everything looks right.  And yet, attempts to connect TO that port at the external IP address of her modem are not completing.  Also, attempts to perform "self-test connectivity confirmation test" from the VNC server on that machine to the RealVNC home web site are also failing to complete.

Has anybody else here had SUCCESS using VNC and HughesNet?  Or similar failure trying, such as I'm having right now?

If tech support is reading this, can you make any further suggestions as to what I might also need to do?  Any questions for me?

Thanks in advance for any help.

[C0RR0SIVE · Accepted solution]

Hughesnet uses CGN, so while ports aren't blocked, forwarding isn't going to be beneficial, and wont allow you to remotely access a system.  You will have to use something like TeamViewer that depends on a middle man server to be able to remotely connect to the client.  Also, be prepaired for a rather nasty delay in doing things remotely... I tend to see about a 1 to 2 second delay when using teamviewer.

Alternatively, you could connect to her IPv6 address if you also have IPv6, however, this usually doesn't work, and the address changes from time to time.

[DSperber]

Many thanks for this very informative explanation.  I did not know about CGN before now, but Wikipedia clearly explains why "direct connect" VNC (which depends on port forwarding in the router) will not work:

"Carrier-grade NAT usually prevents the ISP customers from using port forwarding because the network address translation (NAT) is usually implemented by mapping ports of the NAT devices in the network to other ports in the external interface. This is done so the router will be able to map the responses to the correct device; in carrier-grade NAT networks, even though the router at the consumer end might be configured for port forwarding, the "master router" of the ISP, which runs the CGN, will block this port forwarding because the actual port would not be the port configured by the consumer."

At least Team Viewer works as my fallback connectivity.  So even though it definitely is slow (not only because of the erratic download speed and guaranteed very low upload speed of HughesNet, but also because of the enormous latency implicit in satellite service), at least it is usable.

Incidentally, VNC version 6.1.1 now supports a fee-based seat-based Cloud-based web-facilitated connectivity that uses a non-router approach similar to that of Team Viewer, in addition to the old original "direct connection" approach (which depends on port-forwarding in the router) that I've always used.  It's called "VNC Connect", although I've never used it since I'm already paying to license their direct client/server technology.  In contrast, I use Team Viewer "for personal use" (which is available free for non-commercial use) to support friends and family.

Anyway, again, many thanks for the unfortunate news about why I will not be able to use VNC to support my friend in Florida.  But I've learned something.