QEMU-VNC(1) QEMU QEMU-VNC(1) NAME qemu-vnc - QEMU standalone VNC server SYNOPSIS qemu-vnc [OPTION]... DESCRIPTION qemu-vnc is a standalone VNC server that connects to a running QEMU in- stance via the D-Bus display interface (D-Bus display). It serves the guest display, input, audio, clipboard, and serial console chardevs over the VNC protocol, allowing VNC clients to interact with the virtual machine without QEMU itself binding a VNC socket. OPTIONS -h, --help Display help and exit. -V, --version Print version information and exit. -a ADDRESS, --dbus-address=ADDRESS D-Bus address to connect to. When not specified, qemu-vnc connects to the session bus. -p FD, --dbus-p2p-fd=FD File descriptor of an inherited Unix socket for a peer-to-peer D-Bus connection to QEMU. This is mutually exclusive with --dbus-address and --bus-name. -n NAME, --bus-name=NAME D-Bus bus name of the QEMU instance to connect to. The default is org.qemu. When a custom --dbus-address is given without a bus name, peer-to-peer D-Bus is used. -W, --wait Wait for the D-Bus bus name to appear. Only for bus connections. --password Require VNC password authentication from connecting clients. The password is set at runtime via the D-Bus SetPassword method (see D-Bus VNC). Clients will not be able to connect until a password has been set. This option is ignored when a systemd credential password is present, since password authentication is already enabled via pass- word-secret in that case. -l ADDR, --vnc-addr=ADDR VNC listen address in the same format as the QEMU -vnc option (de- fault localhost:0, i.e. TCP port 5900). -w ADDR, --websocket=ADDR Enable WebSocket transport on the given address. ADDR can be a port number or an address:port pair. -O OBJDEF, --object=OBJDEF Create a QEMU user-creatable object. OBJDEF uses the same key=value syntax as the QEMU -object option. This option may be given multiple times. It is needed, for example, to create authorization objects referenced by --tls-authz. -t DIR, --tls-creds=DIR Directory containing TLS x509 credentials (ca-cert.pem, server-cert.pem, server-key.pem). When specified, the VNC server re- quires TLS from connecting clients. --tls-authz=ID ID of a QAuthZ object previously created with --object for TLS client certificate authorization. When specified, the TLS creden- tials are created with verify-peer=yes so connecting clients must present a valid certificate. After the TLS handshake, the client certificate Distinguished Name is checked against the authorization object. This option requires --tls-creds. --sasl Require that the client use SASL to authenticate with the VNC server. The exact choice of authentication method used is controlled from the system / user's SASL configuration file for the 'qemu' ser- vice. This is typically found in /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user, an environment variable SASL_CONF_PATH can be used to make it search alternate locations for the service config. While some SASL auth methods can also provide data encryp- tion (eg GSSAPI), it is recommended that SASL always be combined with the 'tls' and 'x509' settings to enable use of SSL and server certificates. This ensures a data encryption preventing compromise of authentication credentials. See the VNC security section in the System Emulation Users Guide for details on using SASL authentica- tion. --sasl-authz=ID ID of a QAuthZ object previously created with --object for SASL username authorization. After successful SASL authentication, the authenticated username is checked against the authorization object. If the check fails, the client is disconnected. This option requires --sasl. -s POLICY, --share=POLICY Set display sharing policy. POLICY is one of allow-exclusive, force-shared, or ignore. allow-exclusive allows clients to ask for exclusive access. As sug- gested by the RFB spec this is implemented by dropping other connec- tions. Connecting multiple clients in parallel requires all clients asking for a shared session (vncviewer: -shared switch). This is the default. force-shared disables exclusive client access. Useful for shared desktop sessions, where you don't want someone forgetting to specify -shared disconnect everybody else. ignore completely ignores the shared flag and allows everybody to connect unconditionally. Doesn't conform to the RFB spec but is tra- ditional QEMU behavior. -C NAME, --vt-chardev=NAME Chardev type name to expose as a VNC text console. This option may be given multiple times to expose several chardevs. When not speci- fied, the defaults org.qemu.console.serial.0 and org.qemu.moni- tor.hmp.0 are used. -N, --no-vt Do not expose any chardevs as text consoles. This overrides the de- fault chardev list and any --vt-chardev options. -k LAYOUT, --keyboard-layout=LAYOUT Keyboard layout (e.g. en-us). Passed through to the VNC server for key-code translation. --lossy Enable lossy compression methods (gradient, JPEG, ...). If this op- tion is set, VNC client may receive lossy framebuffer updates de- pending on its encoding settings. Enabling this option can save a lot of bandwidth at the expense of quality. --non-adaptive Disable adaptive encodings. Adaptive encodings are enabled by de- fault. An adaptive encoding will try to detect frequently updated screen regions, and send updates in these regions using a lossy en- coding (like JPEG). This can be really helpful to save bandwidth when playing videos. Disabling adaptive encodings restores the orig- inal static behavior of encodings like Tight. -T, --trace [[enable=]PATTERN][,events=FILE][,file=FILE] Specify tracing options. [enable=]PATTERN Immediately enable events matching PATTERN (either event name or a globbing pattern). This option is only available if QEMU has been compiled with the simple, log or ftrace tracing backend. To specify multiple events or patterns, specify the -trace option multiple times. Use -trace help to print a list of names of trace points. events=FILE Immediately enable events listed in FILE. The file must contain one event name (as listed in the trace-events-all file) per line; globbing patterns are accepted too. This option is only avail- able if QEMU has been compiled with the simple, log or ftrace tracing backend. file=FILE Log output traces to FILE. This option is only available if QEMU has been compiled with the simple tracing backend. EXAMPLES Start QEMU with the D-Bus display backend: qemu-system-x86_64 -display dbus ... Then attach qemu-vnc: qemu-vnc A VNC client can now connect to localhost:5900. To listen on a different port with TLS: qemu-vnc --vnc-addr localhost:1 --tls-creds /etc/pki/qemu-vnc To require TLS with client certificate authorization: qemu-vnc --object authz-list-file,id=auth0,filename=/etc/qemu/vnc.acl,refresh=on \ --tls-creds /etc/pki/qemu-vnc --tls-authz auth0 To enable SASL authentication with TLS: qemu-vnc --tls-creds /etc/pki/qemu-vnc --sasl VNC PASSWORD AUTHENTICATION There are two ways to enable VNC password authentication: 1. --password flag -- start qemu-vnc with --password and then set the pass- word at runtime using the D-Bus SetPassword method. Clients will be re- jected until a password is set. 2. systemd credentials -- if the CREDENTIALS_DIRECTORY environment variable is set (see systemd.exec(5)) and contains a file named vnc-password, the VNC server will use that file's contents as the password automatically. The --password flag is not needed in this case. D-BUS INTERFACE qemu-vnc exposes a D-Bus interface for management and monitoring of VNC connections. See D-Bus VNC for the full interface reference. SEE ALSO qemu(1), D-Bus display, D-Bus VNC, The RFB Protocol COPYRIGHT 2026, The QEMU Project Developers 11.0.50 Aug 28, 2026 QEMU-VNC(1)
NAME | SYNOPSIS | DESCRIPTION | OPTIONS | EXAMPLES | VNC PASSWORD AUTHENTICATION | D-BUS INTERFACE | SEE ALSO | COPYRIGHT
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