kasmtech
Connection disconnected when running KasmVNC on default user
Describe the bug I have proxmox host that runs xubuntu VM and the traffic is going through NAT like this: Internet -> public_ip:8444 -> [DNAT] -> 10.0.0.2:8444 (VM) 10.0.0.2:8444 (VM) -> [SNAT/MASQUERADE] -> public_ip -> Client
and nginx works, so no problem there. But trying to run kasmVNC and connecting through Chrome first shows that it's connected after which instantly it says "Disconnected", in F12 in Chrome I see some 401 Unauthorized requests.
Curiously in firefox all requests are OK (change protocols to websocket request 101 is also OK)
but it still gets disconnected.
This is failing log: vnc-log.log
So I tried creating new user, copying kasmvnc.yaml and running vncserver there and..it looks like it works now! I'm attaching working log working-log-other-user.log Looks like there are still some errors there, but it works..
This is process tree dump: process_tree.txt Note that default user is 'u' and the new one is 'rem' and there I ran vncserver successfully.
System Description
PRETTY_NAME="Ubuntu 24.04.1 LTS"
NAME="Ubuntu"
VERSION_ID="24.04"
VERSION="24.04.1 LTS (Noble Numbat)"
VERSION_CODENAME=noble
ID=ubuntu
ID_LIKE=debian
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
UBUNTU_CODENAME=noble
LOGO=ubuntu-logo
Linux 0polaroid34 6.8.0-39-generic #
39-Ubuntu SMP PREEMPT_DYNAMIC Fri Jul 5 21:49:14 UTC 2024 x86_64 x86_64 x86_64 GNU/Linux
KasmVNC Details
Provide the filename of the package you installed KasmVNC with. The filename includes important details like the OS, architecture, and commit sha.
kasmvncserver_noble_1.3.3_amd64.deb
Provide the output of this command.
Xvnc -version
XVnc: command not found
when directly calling:
/usr/bin/Xvnc -version
Xvnc KasmVNC 1.3.3.0ebbbc6412e131092308cc1ce10b9d106e3b4e05 - built Oct 30 2024 14:13:20
Copyright (C) 1999-2018 KasmVNC Team and many others (see README.me)
See http://kasmweb.com for information on KasmVNC.
Underlying X server release 12008000, The X.Org Foundation
To Reproduce Steps to reproduce the behavior (for non-installation issues):
- Install kasmvnc on xubuntu 24
- Run vncserver no default user
- Try to connect through chrome
- See error
Expected behavior Should connect without issues.
Browser
- Device: PC
- OS: Windows 11
- Browser Chrome Version 131.0.6778.205 (Official Build) (64-bit)
- Firefox 133.0.3 (64-bit)
Additional context
I had to do kasmvnc.yaml settings like this:
logging:
log_writer_name: all
log_dest: logfile
level: 100
network:
protocol: http
interface: 0.0.0.0
websocket_port: 8444
use_ipv4: true
use_ipv6: true
udp:
public_ip: auto
port: 8444
stun_server: auto
ssl:
pem_certificate: /etc/ssl/certs/ssl-cert-snakeoil.pem
pem_key: /etc/ssl/private/ssl-cert-snakeoil.key
require_ssl: true
# unix_relay:
# name:
# path:
security:
brute_force_protection:
blacklist_threshold: 0
blacklist_timeout: 0
because with brute force security it blocks me right away because it looks like the connection is dropping many times in a row.
Before trying to start vncserver I ran x11vnc as a root on display :0, but it should not conflict, because I disabled it.
Or so I thought it works on fresh user but now when I recreated it once again I have this error:
2024-12-22 15:14:49,274 [DEBUG] SConnection: reading protocol version
2024-12-22 15:14:49,275 [INFO] SConnection: Client needs protocol version 3.8
2024-12-22 15:14:49,296 [INFO] websocket 67: got client connection from 10.0.0.1
2024-12-22 15:14:49,298 [INFO] websocket 68: got client connection from 10.0.0.1
2024-12-22 15:14:49,300 [DEBUG] SConnection: processing security type message
2024-12-22 15:14:49,300 [INFO] SConnection: Client requests security type VncAuth(2)
2024-12-22 15:14:49,300 [DEBUG] SConnection: processing security message
2024-12-22 15:14:49,325 [DEBUG] websocket 67: using SSL socket
2024-12-22 15:14:49,327 [DEBUG] websocket 68: using SSL socket
2024-12-22 15:14:49,327 [DEBUG] websocket 67: BasicAuth matched
2024-12-22 15:14:49,327 [DEBUG] websocket 67: Invalid WS request, maybe a HTTP one
2024-12-22 15:14:49,327 [DEBUG] websocket 67: Requested file '/app/images/icons/368_kasm_logo_only_16x16.png'
2024-12-22 15:14:49,328 [INFO] websocket 67: 10.0.0.1 10.0.0.1 rem "GET /app/images/icons/368_kasm_logo_only_16x16.png HTTP/1.1" 200 6221
2024-12-22 15:14:49,328 [DEBUG] websocket 67: No connection after handshake
2024-12-22 15:14:49,328 [DEBUG] websocket 67: handler exit
2024-12-22 15:14:49,328 [DEBUG] SConnection: processing security message
2024-12-22 15:14:49,328 [DEBUG] SVncAuth: reading password file
2024-12-22 15:14:49,328 [PRIO] SConnection: AuthFailureException: Authentication failure: Unable to query the local user to accept the connection.
2024-12-22 15:14:49,329 [DEBUG] XserverDesktop: client gone, sock 42
2024-12-22 15:14:49,329 [PRIO] Connections: closed: [email protected]_1734876889.165055::websocket (Authentication failure: Unable to query the local user to accept the connecti
AuthFailureException: Authentication failure: Unable to query the local user to accept the connection. I have no idea what is going on...
From your log I see this line...
2024-12-22 00:39:33,970 [PRIO] VNCSConnST: User has no read permissions. If this is not intended, grant them permissions with kasmvncpasswd or via the API
This indicates that the kasmvnc user you created does not read access. Make sure you use the correct flags when creating the user...
vncpasswd -u my_username -w -r
