Dear all,

I'm currently having the following issue in RedHat 7.2: because I need to access my computer at work remotely I was planning to use TigerVNC and since I had no idea how set this up I followed a tutorial. To my surprise erything went quite well - until I wanted to actually access my machine with VNC viewer. Because after establishing a connection and typing in my VNC-password I was immediately greeted by THIS error message. Of course I checked /var/log/messages to find out what went wrong but since I'm very very new to Linux I couldn't really make sense of it:

Apr 15 18:47:31 rrel001 fprintd: ** Message: entering main loop
Apr 15 18:47:31 rrel001 systemd: Started Fingerprint Authentication Daemon.
Apr 15 18:47:39 rrel001 systemd: Started Remote desktop service (VNC).
Apr 15 18:48:01 rrel001 fprintd: ** Message: No devices in use, exit
Apr 15 18:48:33 rrel001 dbus[659]: [system] Activating via systemd: service name='org.freedesktop.hostname1' unit='dbus-org.freedesktop.hostname1.service'
Apr 15 18:48:33 rrel001 dbus-daemon: dbus[659]: [system] Activating via systemd: service name='org.freedesktop.hostname1' unit='dbus-org.freedesktop.hostname1.service'
Apr 15 18:48:33 rrel001 systemd: Starting Hostname Service...
Apr 15 18:48:33 rrel001 dbus[659]: [system] Successfully activated service 'org.freedesktop.hostname1'
Apr 15 18:48:33 rrel001 dbus-daemon: dbus[659]: [system] Successfully activated service 'org.freedesktop.hostname1'
Apr 15 18:48:33 rrel001 systemd: Started Hostname Service.

Based on the error message and the log: do you guys have any idea what went wrong and how to fix it?

Thank you for your help!

Daniel

Looks like you're using a Mac...what VNC client are you using? Are you sure the VNC server is at fault, and have you checked the CLIENT piece? Tried a different VNC client?

And TigerVNC is supported in RHEL7, and has installation instructions on the RHEL knowledgebase:
https://access.redhat.com/documentat...-TigerVNC.html

...which would be better to follow than those for CentOS (although it SHOULDN'T matter), and to use the package for RHEL. Since you're using RHEL 7 you are PAYING for it, right??? Because if you're not, you're missing patches/updates/fixes that may be part of the problem. If you're subscribed, and since you're new to Linux/RHEL, you can call Red Hat support for help, and they can walk you through things.

But the best piece of advice I can give you is: don't use VNC. There's really no need. You can connect to your server with SSH, and still run X applications, just as if you were sitting at your desk, with far less overhead and far MORE security. Your local machine needs to have incoming X sessions allowed (typically by running "xhost +"), then when you ssh, run it with "ssh -X user@address", and your display will be set to be your local workstation.

Thank you for your quick reply! RHEL 7.2 was installed and configured by an external IT service, who is probably paying for it Because of this I'm not sure whether or not I can contact the Red Hat support directly or if the IT guys have to do it, who charge an insane amount of money for stuff like that (which is why I'd like to avoid involving them...).
As for the VNC client, I've been using the RealVNC viewer (both the Win and OSX Versions) to remotely access Windows Computers for the past couple of years and so I was planning to also use it for Linux. Now that you mention it I will of course also try another client as soon as I get back to the office on Monday. I will also read through the VNC installation instructions from RHEL then, thank you for the link.

I was planning to use VNC to check the progress of long-running simulations, start new simulations and access the files I have on the Linux-partition. Is this also possible with what you're proposing?

Well, I'm not sure what they are paying for, and they may NOT be paying for RHEL at all. Worth a question to them, since (if they're not), you can then ask WHY you're using licensed software that can't be updated, and why they didn't install the free, identical version of RHEL (CentOS) instead. At the very least, it may get you a free service call.

On a more serious note, you really SHOULD ask them, since if your system is not registered, you won't get bugfixes or security updates, and you'll be stuck with a production system that's unstable and vulnerable.
RealVNC is a decent client, but there are differences between VNC and RDP. In your case, I'd check out the RHEL instructions and go back through them first, before trying another client. Could be a minor difference.
Absolutely. You can access any application (either GUI or CLI) via X-windows/SSH. VNC is good if you need a 'console' type setup, but it's overkill for most things these days.

A quick test you can run is by enabling remote X sessions on your local machine via the "xhost +" command. Once you do that, "ssh -X user@remote.machine.com", and type in "xclock". You *SHOULD* see the x-windows clock pop up on your local machine...it's RUNNING on your remote system, but DISPLAYING locally. Same with Firefox, or any other GUI based app. If you're using CLI, then ssh is all you need. You can mount the remote directories LOCALLY with sshfs, and use it as just another disk.

OMG TB0ne thank you so much for providing me with that link to the RHEL knowledge base! As it turns out the "Sharing an Existing Desktop"-option is exactly what I was looking for and after following the described steps and configuring the firewall accordingly I can now successfully establish a remote desktop connection
There's just one more thing I'd like to ask: is it possible to encrypt this connection or does SSH require a VNC server?

Nope...SSH is its own animal, and performs pretty good encryption.

Personally, I think VNC is overkill, but if it's what you need, then I'm happy it worked out for you.

So I guess that's a no, Desktop Sharing can't use encrypted connections ?

On a completely unrelated note, do you by any chance know what graphics API RHEL uses? I'd have guessed OpenGL but with all the peculiarities I've experienced so far I'm really not sure... Is it maybe hardware-specific? My machine uses an nVidia NVS 310 graphics card with some nVidia driver installed.

You *CAN*, but you'll need to use a different VNC package that supports it.
Peculiarities where? On your console or over VNC? The nVidia cards are well supported under Linux, and you can get the drivers from nVidia's website...fairly easy to install. That will NOT have any effect on the VNC connection, though.

Please listen to the above advice recommending to NOT use VNC.

VNC, and programs like it, are the "Windows way" of remotely accessing a machine. They are generally far less secure (sometimes very INsecure), and use FAR more overhead than the "proper" alternatives. There are VERY VERY few use-cases where full remote desktop access is required. The VAST majority of cases do not need it, all of that extra bloat just compromises latency, speed, and security.

Literally none of that requires a giant remote desktop style solution, or even X forwarding at all, unless these "simulations" you speak of can only be started, monitored, or controlled from a GUI.

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