VNC over VPN on Mac

VPN
1

I’m stumped. I want to connect to a Mac using VNC Viewer. If the VNC client is on the same physical LAN as the VNC server, I can connect no problem. The problem occurs when I take the client computer offsite and attempt to connect the same VNC server over a VPN connection. The server device is pingable over the VPN, but the VNC connection to it seems blocked. There is no firewall software running the VNC server. Is it possible that the VNC Server software itself is blocking inbound requests from remote/VPN networks… and is there a work-around?

2

The server device is pingable over the VPN

So? Is the actual TCP port reachable? Try nmapping it in a unix shell, or test net-connection on powershell.

Try checking the firewall rules on the system you’re vncing into, also.

Ping only tells you if the system is reachable on the network. It does not tell you if the service can be connected to. I’m not sure why so many techs stop here when they test connectivity with ping. It’s an incomplete test.

If the firewall rules allow it, but you can’t hit the tcp port, check devices in between, including vpn settings. The traffic would be filtered in between somehow.

3

You need to speak to whomever is running the network.

It’s possible that the server device is not listening on the network you are on when you come over the VPN.

Or the VPN tunnel might only allow specific traffic.

Or a few other things that come to mind. The network management team can say better.

4

You can use a tunneling service such as https://pinggy.io/ . It does not require you to install anything either,

You can run a command as ssh -p 443 -R0:localhost:5900 [email protected] .

This will give you an address and port for example: tljocjkijs.a.pinggy.link:40527

Using this you will be able to connect to the VNC server from a different network.

See this blog for a better idea: Remote Desktop for Raspberry Pi and other IoT devices

5

i use ssh tunnels to achieve this without vpns.

6

Thanks. The host is a Mac, and I’m using their default VNC integration. NMAP appears good.

PORT STATE SERVICE VERSION
5900/tcp open vnc?

The Mac’s firewall is turned off and there is no other, 3rd-party firewall running on the machine.

7

Thanks for sharing about pinggy.io. First I’ve heard of it.

8

also, what device is terminating the VPN? the Mac Host? if not the Mac, then is it the same device as the Macs default gateway? how do you know what device is actually responding to the ICMP pings?