Can't connect to my Ubuntu VM running inside Proxmox using Guacamole! --help

Kitamime

New Member
May 4, 2023
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I have tried for 2 days to get guacamole to connect to Ubuntu Lunar Lobster running on my Proxmox server. It just will not I installed xrdp and started the service and then used the rdp protocol in guacamole and port 3389, turned off certificates but it would not connect. So, I tried VNC and turned on remote access in the Ubuntu share settings and set the port to 5900, still it would not connect. Strangely enough it does connect to my Ubuntu Server running inside the same Proxmox server and the terminal shows up. Idk what I'm doing wrong and I've tried all I know....please someone help.
 
So to clarify: you have two VMs running on your hypervisor. You are trying to connect to these VMs using variety of remote access protocols.
One VM works and the other doesnt.
If I understand it correctly there is no virtual hardware dependencies. These are network protocols so initial troubleshooting should be around the network. What have you done to troubleshoot it?

Things to try and report on :
- can you ping ?
- can you ssh ?
- can you connect to the port locally ? nc localhost 5900
- can you connect to public IP from the host itself ? nc ip_of_host 5900
- can you connect to the public IP/port from remote host ? nc ip_of_host 5900
- is there a firewall running and if there is, have you tried to stop it?

In short, it doesnt look like your issue is related to "Proxmox VE: Installation and configuration".


Blockbridge : Ultra low latency all-NVME shared storage for Proxmox - https://www.blockbridge.com/proxmox
 
So to clarify: you have two VMs running on your hypervisor. You are trying to connect to these VMs using variety of remote access protocols.
One VM works and the other doesnt.
If I understand it correctly there is no virtual hardware dependencies. These are network protocols so initial troubleshooting should be around the network. What have you done to troubleshoot it?

Things to try and report on :
- can you ping ?
- can you ssh ?
- can you connect to the port locally ? nc localhost 5900
- can you connect to public IP from the host itself ? nc ip_of_host 5900
- can you connect to the public IP/port from remote host ? nc ip_of_host 5900
- is there a firewall running and if there is, have you tried to stop it?

In short, it doesnt look like your issue is related to "Proxmox VE: Installation and configuration".


Blockbridge : Ultra low latency all-NVME shared storage for Proxmox - https://www.blockbridge.com/proxmox
I'm going to try all of these soon as I get home in about 20 mins but to ping can I and connect locally I can use the Proxmox shell right? Sorry new to all this...
 
to ping can I and connect locally I can use the Proxmox shell right?
the ping/ssh test is only interesting from remote host, ie your windows workstation.
the "nc" test initially should be done from the VM itself, either via ssh or console.
you could then use proxmox as remote host as well, but an actual remote host would be more helpful.


Blockbridge : Ultra low latency all-NVME shared storage for Proxmox - https://www.blockbridge.com/proxmox
 
I'm going to try all of these soon as I get home in about 20 mins but to ping can I and connect locally I can use the Proxmox shell right? Sorry new to all this...
 

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So here's some images so hopefully it can help ...the 1st one from left to right is how my Proxmox is setup with the vm's. The next one is where i was in the pve shell console and could indeed ping my ubuntu Lunar Lobster VM. The 3rd image is where i tried to start ssh on my Lunar Loster VM but it didn't have ssh installed thus I installed openssh-server on it and then used the pve to ssh into it which is shown in the last two images....so i wanna be about to see the desktop using Guacamole and rdp of vnc but cant seem to get it working.
 
Here's how my Guacamole is setup with RDP and the error i get...i try reconnecting but nothing.
 

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- can you connect to the public IP/port from remote host ? nc ip_of_host 5900
there are no ":" in my example of the command. You can always check the manual page as well:
man nc
Code:
ncat [OPTIONS...] [hostname] [port]

Having said that, I am satisfied that your VM appears to be reachable on the network (at least from PVE). So at this point you should concentrate on properly configuring the VNC/RDP services within your VM. Confirm that you can access the ports they are listening on, both with "nc" and actual VNC client. Then continue on with your Guacamole setup.



Blockbridge : Ultra low latency all-NVME shared storage for Proxmox - https://www.blockbridge.com/proxmox
 
Here's me trying to SSH into it after starting ssh on the ubuntu Lunar Lobster vm and the same error...
 

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there are no ":" in my example of the command. You can always check the manual page as well:
man nc
Code:
ncat [OPTIONS...] [hostname] [port]

Having said that, I am satisfied that your VM appears to be reachable on the network (at least from PVE). So at this point you should concentrate on properly configuring the VNC/RDP services within your VM. Confirm that you can access the ports they are listening on, both with "nc" and actual VNC client. Then continue on with your Guacamole setup.



Blockbridge : Ultra low latency all-NVME shared storage for Proxmox - https://www.blockbridge.com/proxmox
I used nc 192.168.1.145 5900 and got this
 

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I used nc 192.168.1.145 5900 and got this
now do the same inside the VM, ie connect to itself. If you get identical result - there is no service running on the VM that you think should be running there and listening on that port.


Blockbridge : Ultra low latency all-NVME shared storage for Proxmox - https://www.blockbridge.com/proxmox
 
Last edited:
heres the results of a ping and nc on the Ubuntu Lunar Lobster vm
 

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To reiterate, none of this has anything to do with Proxmox as a hypervisor. I recommend investing some time in studying basic Linux management and troubleshooting.
For your latest screenshot: being able to ping itself is expected, if that didnt work it would mean you have broken your VM installation at a very fundamental basis. The "nc" command seems to be able to open the port, which means its possibly a firewall issue. Try to stop whatever firewall is in use on your VM, possibly "systemctl stop firewalld"


Blockbridge : Ultra low latency all-NVME shared storage for Proxmox - https://www.blockbridge.com/proxmox
 
so then i decided to setup a listner using nc -l -p 3389 on the Ubuntu Lunar Lobster vm to see if any request where reaching it ....well seems that port is in use (pic 1) so i changed the guacamole connection to port 3380 and got this back (pic 2)
 

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To reiterate, none of this has anything to do with Proxmox as a hypervisor. I recommend investing some time in studying basic Linux management and troubleshooting.
For your latest screenshot: being able to ping itself is expected, if that didnt work it would mean you have broken your VM installation at a very fundamental basis. The "nc" command seems to be able to open the port, which means its possibly a firewall issue. Try to stop whatever firewall is in use on your VM, possibly "systemctl stop firewalld"


Blockbridge : Ultra low latency all-NVME shared storage for Proxmox - https://www.blockbridge.com/proxmi
I stopped the firewall and went in and configured the sharing option in the vm but nothing...ugh I'm going to try another distro and see where that takes me...Perhaps I did something wrong in this one. idk
 
If I understood the problem correctly, I understood that the screen went black after the login screen. If you change the video card to SPICE, the problem is fixed.
 
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If I understood the problem correctly, I understood that the screen went black after the login screen. If you change the video card to SPICE, the problem is fixed.
I'll have to try that but also going to have to get around the firewall of my ISP as they want me to have a business account for port forwarding and its absurd thus I'm just gonna use Cloudflare as it works without need of a static IP.
 

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