KasmVNC provides remote web-based access to a Desktop or application. While VNC is in the name, KasmVNC differs from other VNC variants such as TigerVNC, RealVNC, and TurboVNC. KasmVNC has broken from the RFB specification which defines VNC, in order to support modern technologies and increase security. KasmVNC is accessed by users from any modern browser and does not support legacy VNC viewer applications. KasmVNC uses a modern YAML based configuration at the server and user level, allowing for ease of management.
Kasm Technologies developed Kasm Workspaces, the Containerized Streaming Platform. Kasm has open-sourced the Workspace docker images, which include containerized full desktops and apps and base images intended for developers to create customized streaming containers. These containers can be used standalone or within the Kasm Workspaces Platform which provides a full Enterprise feature set.
Do not use the README from the master branch, unless you are compiling KasmVNC yourself from the tip of master. Use the documentation for your specific release.
For beta releases prior to version 1.0.0, use the README in this github project on the tagged commit for that release.
You must disconnect and reconnect to the server after installation, for the group membership to apply.
# Please choose the package for your distro here (under Assets):
# https://github.com/kasmtech/KasmVNC/releases
wget <package_url>
sudo apt-get install ./kasmvncserver_*.deb
# Add your user to the ssl-cert group
sudo adduser $USER ssl-cert# Please choose the package for your distro here (under Assets):
# https://github.com/kasmtech/KasmVNC/releases
wget <package_url>
# Ensure KasmVNC dependencies are available
sudo dnf config-manager --set-enabled ol8_codeready_builder
sudo dnf install oracle-epel-release-el8
sudo dnf localinstall ./kasmvncserver_*.rpm
# Add your user to the kasmvnc-cert group
sudo usermod -a -G kasmvnc-cert $USER# Please choose the package for your distro here (under Assets):
# https://github.com/kasmtech/KasmVNC/releases
wget <package_url>
# Ensure KasmVNC dependencies are available
sudo yum install epel-release
sudo yum install ./kasmvncserver_*.rpm
# Add your user to the kasmvnc-cert group
sudo usermod -a -G kasmvnc-cert $USERThe following examples provide basic usage of KasmVNC with the tools provided. For full documentation on all the utilities and the runtime environment, see our KasmVNC Documentation
# Start a session and be guided to setup a user and select a default desktop environment
vncserver
# Start a session with the mate desktop environment
vncserver -select-de mate
# Add a new user with read/write permissions
vncpasswd -u my_username -w -r
# Tail the logs
tail -f ~/.vnc/*.log
# Get a list of current sessions with display IDs
vncserver -list
# Kill the VNC session with display ID :2
vncserver -kill :2KasmVNC is configured via YAML based configurations. The server level configuration is at /etc/kasmvnc/kasmvnc.yaml. Edits to this file apply to all users. Individual users can override server global configurations by specifying them in their configuration file at ~/.vnc/kasmvnc.yaml.
The following configuration shows all default settings. Many of the encoding settings can be overridden by the client, unless the runtime_configuration.allow_client_to_override_kasm_server_settings setting is set tot false. By default the client is allowed to modify encoding settings.
For a full description of each setting see the configuration reference.
desktop:
resolution:
width: 1024
height: 768
allow_resize: true
pixel_depth: 24
gpu:
hw3d: false
drinode: /dev/dri/renderD128
network:
protocol: http
interface: 0.0.0.0
websocket_port: auto
use_ipv4: true
use_ipv6: true
udp:
public_ip: auto
port: auto
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
user_session:
new_session_disconnects_existing_exclusive_session: false
concurrent_connections_prompt: false
concurrent_connections_prompt_timeout: 10
idle_timeout: never
keyboard:
remap_keys:
ignore_numlock: false
raw_keyboard: false
pointer:
enabled: true
runtime_configuration:
allow_client_to_override_kasm_server_settings: true
allow_override_standard_vnc_server_settings: true
allow_override_list:
- pointer.enabled
- data_loss_prevention.clipboard.server_to_client.enabled
- data_loss_prevention.clipboard.client_to_server.enabled
- data_loss_prevention.clipboard.server_to_client.primary_clipboard_enabled
logging:
log_writer_name: all
log_dest: logfile
level: 30
security:
brute_force_protection:
blacklist_threshold: 5
blacklist_timeout: 10
data_loss_prevention:
visible_region:
# top: 10
# left: 10
# right: 40
# bottom: 40
concealed_region:
allow_click_down: false
allow_click_release: false
clipboard:
delay_between_operations: none
allow_mimetypes:
- chromium/x-web-custom-data
- text/html
- image/png
server_to_client:
enabled: true
size: unlimited
primary_clipboard_enabled: false
client_to_server:
enabled: true
size: unlimited
keyboard:
enabled: true
rate_limit: unlimited
logging:
level: off
encoding:
max_frame_rate: 60
full_frame_updates: none
rect_encoding_mode:
min_quality: 7
max_quality: 8
consider_lossless_quality: 10
rectangle_compress_threads: auto
video_encoding_mode:
jpeg_quality: -1
webp_quality: -1
max_resolution:
width: 1920
height: 1080
enter_video_encoding_mode:
time_threshold: 5
area_threshold: 45%
exit_video_encoding_mode:
time_threshold: 3
logging:
level: off
scaling_algorithm: progressive_bilinear
compare_framebuffer: auto
zrle_zlib_level: auto
hextile_improved_compression: true
server:
http:
headers:
- Cross-Origin-Embedder-Policy=require-corp
- Cross-Origin-Opener-Policy=same-origin
httpd_directory: /usr/share/kasmvnc/www
advanced:
x_font_path: auto
kasm_password_file: ${HOME}/.kasmpasswd
x_authority_file: auto
auto_shutdown:
no_user_session_timeout: never
active_user_session_timeout: never
inactive_user_session_timeout: never
command_line:
prompt: true- Faster jpeg compression (via statically linked libjpeg-turbo)
- Webp image compression for better bandwidth usage
- Automatic mixing of webp and jpeg based on CPU availability on server
- Multi-threaded image encoding for smoother frame rate for servers with more cores
- WebRTC UDP Transit
- Lossless QOI Image format for Local LAN
- Full screen video detection, goes into configurable video mode for better full screen videoo playback performance.
- Dynamic jpeg/webp image coompression quality settings based on screen change rates
- Seemless clipboard support (on Chromium based browsers)
- Binary clipboard support for text, images, and formatted text (on Chromium based browsers)
- Allow client to set/change most configuration settings
- Data Loss Prevention features
- Key stroke logging
- Clipboard logging
- Max clipboard transfer size up and down
- Min time between clipboard operations required
- Keyboard input rate limit
- Screen region selection
- Deb packages for Debian, Ubuntu, and Kali Linux included in release.
- RPM packages for CentOS, Oracle, OpenSUSE, Fedora. RPM packages are currently not updatable and not released, though you can build and install them. See build documentation.
- Web API added for remotely controlling and getting information from KasmVNC
- Multi-User support with permissions that can be changed via the API
- Web UI uses a webpack for faster load times.
- Network and CPU bottleneck statistics
- Relative cursor support (game pointer mode)
- Cursor lock
- IME support for languages with extended characters
- Better mobile support
- DRI3 GPU acceleration with open source drivers (AMDGPU,Intel,ATI,ARM)
Future Goals:
- H264 encoding
See the builder/README.md. We containerize our build systems to ensure highly repeatable builds.
See the LICENSE.TXT and ACKNOWLEDGEMENTS.md