You are not logged in.

#1 2021-06-14 15:07:09

laanan
Member
Registered: 2020-01-25
Posts: 35

Strange VNC Behavior?

Hello all,

I'm trying to figure out a VNC related issue and thought I'd seek advice from you friendly folks.

I'm running x0vncserver at work on display :0 and would like to be able to connect from home and see my screen at work (screen scraping style).

I've gotten this configuration working before, but I am running into a bit of a weird problem. When I connect from home, all I get is a blank screen. I've used a couple different VNC viewers (my preference is Remmina) with the same behavior. I tested out the set up with a laptop at work, while at work, running a Bunsen live cd, and I had no problem seeing my desktop on the "work" computer. However, at home, still blank. I even tried my wife's (*shiver*) Macbook -- still blank black screen.

Work and home are connected site to site via Sonicwall firewalls, and so share a network.

Anyway, I'm stumped and hoping someone can point me in the right direction. A basic explanation about how "displays" work would be great, if edifying. The X server is a pretty mysterious thing to me. For example, if I start the x0vncserver on display :1, what does that mean??? Would display :1 be like a virtual display (in that it is not connected to an actual monitor)? Spooky stuff.

Offline

#2 2021-06-14 21:29:02

laanan
Member
Registered: 2020-01-25
Posts: 35

Re: Strange VNC Behavior?

Update -- So I discovered that at least one issue is the screen locking function. If I leave my screen unlocked, then I can connect over VNC and see my screen. So, I tried connecting via SSH first and killing light-locker, the screen locker in use. No dice. Any suggestions?

Offline

#3 2021-06-14 21:55:48

rbh
Member
From: Sweden/Vasterbotten/Rusfors
Registered: 2016-08-11
Posts: 1,082

Re: Strange VNC Behavior?

What is the response to cli command

$ killall light-locker

Do you need to have screen locked? You know you can right klick the power icon in tint2 systray and choose "Presentation mode", to temporarily disable the screnlock...?


// Regards rbh

Please read before requesting help: Guide to getting help,
Introduction to the Bunsenlabs Lithium Desktop and other help topics under "Help Resources" on the BunsenLabs menu

Offline

#4 2021-06-14 22:17:22

rbh
Member
From: Sweden/Vasterbotten/Rusfors
Registered: 2016-08-11
Posts: 1,082

Re: Strange VNC Behavior?

And,yes, running vncserver other than display :0, vill run an virtual desktop. You can not continue where you left when leaving it, you start a new session


// Regards rbh

Please read before requesting help: Guide to getting help,
Introduction to the Bunsenlabs Lithium Desktop and other help topics under "Help Resources" on the BunsenLabs menu

Offline

#5 2021-06-15 05:13:37

laanan
Member
Registered: 2020-01-25
Posts: 35

Re: Strange VNC Behavior?

rbh,

killing light-locker did not allow me to see my screen over VNC, but it did break the lock function on the work computer. I could no longer click the little lock icon in the lower right corner of my screen to initiate a screen lock, and running light-locker from the command line did not initiate a locked screen. I had to reboot to get back the screen locking function.

Stranger still...

I switched to x11vnc, because, apparently, x0vncserver lacks the ability to grab authority from the x server. I admit that the esoteric realm of x is, for me, the deep end. Anyhow, throwing paint and seeing what sticks has worked for me since Windows 3.1, so what the hell?

So after a lot of trial and error, this command worked: sudo x11vnc -display :0 -auth guess

However, not at first. Initially, this command started up the server and grabbed control of the display from x (I *think* that's how this works), but I still got a blank screen on Remmina. I tried sudo x11vnc -display :1 -auth guess, which, eureka, _did_ allow me see a log in screen, however, when I tried to log in, Remmina crashed. When I tried again, I got a blank screen.

I then tried sudo vs not sudo, thinking that maybe by using sudo I was inadvertently trying to grab a display from the root user (or something like that). I don't remember exactly the difference, but I still could not see my work screen.

For some reason I tried sudo x11vnc -display :0 -auth guess again, and it now works, however, running sudo x11vnc -display :1 -auth guess or for any other display (:2, for example) does not work. I get the error "14/06/2021 22:09:06 -auth guess: failed for display='debian:1'"

I get this error with privileges and without, but, help me here, shouldn't I be able to open as many displays as I want?

Offline

#6 2021-06-15 18:21:27

AndrewSmart
Member
Registered: 2019-06-10
Posts: 29

Re: Strange VNC Behavior?

I highly recommend x2go. More responsive and uses less bandwidth than VNC, due to things like optimizations on top of X11. https://wiki.x2go.org/doku.php/doc:newtox2go

But I suppose anything you manage to get to working may suffice.

Remote Desktop is very useful technology.

Offline

#7 2021-06-16 11:03:11

rbh
Member
From: Sweden/Vasterbotten/Rusfors
Registered: 2016-08-11
Posts: 1,082

Re: Strange VNC Behavior?

I have not run vnc for a couple of yeras. Then it was only on my lan.
Then, I ssh in to the server, started a vnc server, without giving any session id, just "$ vncserver".

The server asked for password gave me the connection information. The first time I started vncserver,the the session was on display :1. If I needed another session and started vncserver again, it was started on display :2.
I could configure vncserver to allways start vncserver on display :0, and attach to that display.

You did not answer me, if you realey need light-locker to run. If not, why not disable it? Permanently or temporarily.
If you need it, do you need to get display:0, or can you be satisfied with starting another display?

What os and what vnc server-program do you use?
I agree with @AndrewSmart, that x2go, might be a better, more modern solution..

Last edited by rbh (2021-06-16 11:04:50)


// Regards rbh

Please read before requesting help: Guide to getting help,
Introduction to the Bunsenlabs Lithium Desktop and other help topics under "Help Resources" on the BunsenLabs menu

Offline

#8 2021-06-16 14:17:55

trinidad
New Member
From: Chicago & Southeast WI
Registered: 2021-04-10
Posts: 2
Website

Re: Strange VNC Behavior?

I use x11vnc for remote desktop connections with Debian. I prefer it because I can alias specifics for its startup script and start and stop it via SSH. However you may not need full desktop access, maybe just using specific applications remotely, which is more efficiently done with SSH x11 forwarding. I have written a bit about using x11vnc and Remmina and SSH x11 forwarding and it may be of help to you to read through some of the following well illustrated material:

https://www.dbts-analytics.com/cruzana.html

TC

Offline

#9 2021-06-23 13:58:17

laanan
Member
Registered: 2020-01-25
Posts: 35

Re: Strange VNC Behavior?

Hi folks, I've been out of town but I'm circling back to report on how things turned out.

I got X2go running. Neat little program that I, admittedly, don't /quite/ understand. Anyhow, what *is* interesting is that the same behavior is replicated (i.e. I get the same blank screen with X2go as with Remmina). From a live cd set up connecting from a laptop to my workstation, I can see my desktop as it is when I log in from the workstation itself. However, when I try the same set up with X2go from home, I get a blank screen. I am thinking it must be some setting or error on my home computer that is causing the issue. I'll try rebooting again and see if that fixes it. I will also try booting from a live cd and seeing if that works. If it does, not sure how to further troubleshoot.

To answer rbh, yes, my office is (*sigh*) a pass-through for my staff, so I need to be able to lock my screen. I can't suspend the session, instead, because I have a web server and (believe it or not) an efax server running on this box.

Side bar question for trinidad -- one weird thing related to x forwarding that I came across in my tinkering and troubleshooting was that, when I forwarded my x from home to work and opened Firefox via ssh on the work computer, the browser that opens at home uses the profile for the home user. This surprised me, since my understanding of x forwarding is I am just telling the remote machine to use my local display instead of the remote display. I even copied the remote Firefox profile to the local Mozilla folder and renamed the local profile, which still did not result in Firefox loading with the remote profile. Instead, a new default profile was used (although a new profile file did not seem to be generated). Isn't this weird?

I suppose I should try uninstalling Firefox on my home computer, forward my x, start Firefox on the remote computer, and see what happens.

Linux is still so mysterious to me ;-)

Last edited by laanan (2021-06-23 15:43:10)

Offline

Board footer

Powered by FluxBB