How to connect to the native (non-VNC) Mac screen sharing from a Windows PC?

Question

I have a Mac with screen sharing enabled through "Remote Management" and not through the "Screen Sharing" setting. I also disable regular VNC since it seems like pretty insecure and I'd like to rely on the Mac's local users' credentials for the screen sharing authentication.

Is there any way to view the screen of such a Mac from a Windows PC?

Solution 1

The Apple Remote Desktop/Screen Sharing is VNC, albeit with some authentication and encryption extensions. You're correct that VNC is not secure when used over an untrusted network, as all keystrokes - including any passwords - are sent unencrypted. You can, however, set up an encrypted tunnel to pipe the VNC through.

The easiest way to do this is with an SSH tunnel. First, turn on "remote login" in the sharing section of System Preferences, as well as checking the "allow VNC viewers" checkbox you point out above. Then, on the Windows computer, download PuTTY and forward a port of your choice (1234, for example) to localhost:5900 on your Mac. When you connect with PuTTY, you'll be prompted for your Mac username and password. Then, start your VNC client on Windows and connect to localhost:1234 (where 1234 is the port you forwarded earlier). If you want to be more paranoid, set up a firewall (the bundled ipfw will do fine; Flying Buttress is a good shareware GUI) to disallow all connections to port 5900 except from localhost (i.e. your tunnel endpoint).

As an aside, I believe this is more or less what Screen Sharing does to provide its more secure Mac to Mac connection, though not using something SSH.

Solution 2

No matter whether you get to it via iChat, "Screen Sharing", or "Remote Management", if you're controlling a remote Mac, you're doing it over the VNC protocol. The only service built into Mac OS X for screen control uses the VNC protocol.

So your underlying question would be better stated as, "How to use Mac-style username+password authentication when VNC'ing into a Mac?"

Comments

[Thalys]

i was under the impression mac screen sharing IS vnc. tried your regular VNC clients with it?

[UrEl]

regular VNC clients can only authenticate with a password, not a combination of username+password as the Mac's screen sharing requires by default.