Configuration Reference

In this chapter all configuration pages within Veyon Configurator as well as all configuration options with their respective meanings are explained in detail. It mainly serves as a reference for looking up detailed configuration options. A manual and hints for the installation can be found in chapter Configuration.

General

User Interface

Language
The selected language can be adapted for the graphical user interfaces as well as the command line tools. You can choose from all the languages that are already provided in a partly or complete translation. Please note, that changing the language will take effect after a program restart. In default configuration Veyon uses the language of the operating system, if this language is already supported. Otherwise, English will be used as a fallback.

Default: use system language settings

High-DPI-Scaling

In case Veyon is used on high resolution screens with a high pixel density (DPI>150) this option should be activated. In this case the user interfaces are displayed larger such that readability especially of visual elements with text caption is improved.

Default: disabled

Logging

You have several options at hand to influce the logging within Veyon. These options are primarily of interest if you are experiencing problems using Veyon. The log files may indicate potential causes for errors.

Logfile directory

You can use this option to specify in which directory the log files will reside. Normally you should use a placeholder variable in this place. A more detailed description about possible values can be found in section placeholder variables.

Default: $TEMP

Loglevel
The loglevel defines how detailed logging messages are recorded. For analysis of program failures it may be useful to even set the loglevel to Debugmessages and everything else. Thus, however, huge amounts of log data can be produced fast. In normal operating mode only warnings and errors should be recorded.

Vorgabe: Information, warnings and errors

Limit logfile size
In order for logfiles not to become too large and occupy memory unnecessarily, their size can be limited with this option. If activated, an upper limit for the size of a single logfile can be configured.

Default: disabled / 1 MB

Rotate logfiles
In conjunction with limiting the size of a single logfile, it may be useful furthermore to rotate the logfiles. In this case one logfile is renamed to Veyon...log.0 after exceeding the configured limit. Previously rotated files are renamed such that the number of the file suffix is increased by 1. If the maximum number of rotations is reached, the oldest file (i.e. the one with the highest number as a suffix) is deleted.

Vorgabe: disabled / 10x

Log to stderr

If program components of Veyon are executed from a command line window (i.e. a terminal), you can use this option to specify, whether logging messages shall be printed to stderr or stdout. This option is primarily relevant for scripting operations.

Default: activated

Log to Windows-Event Log

For in central management in may be useful in some cases to log logging messages directly to the Windows-Event Log. This option does not influence the normal recording of logfiles. Under Linux this option has no effect.

Default: disabled

You can use the Clear all Logfiles button to delete all Veyon logfiles in the logfile directory of the current user as well as the ones of the system service.

Network Object Directory

In Veyon a network object directory provides information about network objects. Network objects include computers and rooms that computer are based in. THe data from the network object directory is used by Veyon Master to supply the computer room management with entries. On top of that data from the network object directory is used for access control. By default a backend is used, that stores the data in the local Veyon configuration and queries them from this location. See section local data for more information.

Backend

You can use this option to define the desired backend for the network object directory. Depending on the installation there may be several backends such as LDAP/AD integration available beside the default backend.

Default: Standard (store objects in local configuration)

Update interval

The network object directory can be automatically updated in the background which may come in handy if dynamic backends such as LDAP are used. The time interval for these updates can be altered with this option.

Default: 60 seconds

Service

General

Hide info area icon

By default the Veyon service displays an info area icon (see also system section of the control panel) to indicate proper operation and information concering program version and used network ports. Displaying the icon can be prohibited by activating this option.

Default: disabled

Activate SAS generation in the software (Ctrl+Alt+Del)

In standard configuration it is not possible for applications running under Windows to generate the Secure-Attention-Sequence (Ctrl+Alt+Del) and simulate pressing these keys. With this option a policy is written to the Windows-Registry that alters this behavior. It is recommended to leave this option activated in order to be able to send Ctrl+Alt+Del to a remotely controlled computer. Otherwise it may for example not possible to unlock the remotely controlled computer. A user login can also be prohibited since the keys Ctrl+Alt+Del usually have to be pressed to this end.

Default: activated

Autostart

With this option you can specify whether the Veyon service is registered as a system service in the operating system meaning that is automatically started on booting the computer.

Default: activated

Additional parameters

If the Veyon service is registered as a system service, you can use this option to supply additional parameters which the operating system passes to the Veyon service upon starting. A more detailed explanation of possible options can be found in section Program Parameters for Veyon Service.

Default: <empty>

Network

Primary service port

You can use this option to define the primary network port the Veyon service is working with, meaning that it listens to incoming connections and accepts them.

Default: 11100

Port of the interval VNC server

You can use this option to define the network port the interval VNC server is working with. This port is not reachable from the outside and is used exclusively by the Veyon service to access screen data via an internal VNC server and forward them.

Default: 11200

Port for function manager

You can use this option to define the network port the function manager is working with. This internal components of the Veyon service is an interface between the Veyon service and function processes. In contrast to the Veyon service these function processes are running in the context of the signed in user and therefore have to communicate with the Veyon service through this interface. This port is not reachable from the outside.

Default: 11300

Port for demo server

You can use this option to define the network port the demo server is working with. The demo server provides screen data from a teacher computer to the network during a demonstration.

Default: 11400

Activate firewall exception

Depending on the system configuration can may be impossible for a process running under Windows to listen to a specific port since the Windows-Firewall may be blocking connection requests. In order to provide access to the service port and the demo server port, exceptions for the Windows-Firewall have to be configured. This is automatically done during the installation process. If this behavior is unwanted and a manual configuration is preferred, this option can be disabled.

Default: activated

Only allow connections from the local computer

If the Veyon service shall not be reachable for other computers in the network, you can use this option. For normal computers which shall be access from the Veyon Master, this option must not be activated. However, the option could be useful for teacher computers in order to provide an additional security layer beside the access control settings. Access to the demo server is not influenced by this option.

Default: disabled

VNC server

Plugin

By default Veyon uses an internal platform specific VNC server implementation to provide the screen data of a computer. In some cases, however, it may be desirable to utilize a plugin with a different implementation. For example if a separate VNC server is already installed on the computer, this server can be used instead of the internal VNC server by choosing the plugin External VNC Server. In this case the password and network port of the installed VNC server have to be entered.

Default: Built-in VNC server

Master

Directories

In order to make a configuration generic and independent of the user, you should use placeholder variables instead of absolute paths in the directory settings. A more detailed explanation of possible values can be found in section placeholder variables.

User configuration

The user specific configuration of the Master program resides in the directory defined here. This configuration includes the settings for the user interface and the computer choice from the last session.

Default: $APPDATA/Config

Screenshots

All image files that have been generated by the screenshot function reside in the directory defined here. For example if you want to store the files in a central collection folder, a different directory path can be entered here.

Default: $APPDATA/Screenshots

Behavior

Perform access control on program start

You can use this option to define whether the possibly configured computer access control should also be perform whenever the Veyon Master is started. Even though access control is enforced on client-side in every case, this additional option assures, that users without proper access rights can not even start the Veyon Master, hence making security even more visible.

Default: disabled

Automatically switch to current room

By default all computers that have been selected the previous time are displayed after starting Veyon Master. If instead all computers in the Master computer’s room shall be displayed, this option can be activated. The Veyon Master will then try to solve which room the local computer belongs to using the configured network object directory. All computers in the room are listed in this case. Precondition for this function is a correctly working DNS setup in the network which translated computer names to IP addresses and vice versa.

Default: disabled

Adjust computers’ thumbnail size automatically upon starting

If the size of the computers’ thumbnail is to be automatically adjusted upon starting Veyon Master (takes the same effect as clicking the Auto button), this option can be activated. The previously configured size will be ignored. This functionality primarily comes into play in conjunction with the automatic room change.

Default: disabled

Enforce chosen mode for client computer

Some of Veyon’s functions change the operating mode of a computer. Examples are the demo mode or the screen lock. These mode function are activated only once per default and, for example, are not restored in case of a physical computer reboot. If this option is activated, the mode will even be enforced after a connection has been closed.

Default: disabled

Show confirm dialogue for potentially hazardous actions

Actions such as rebooting a computer or logging off of a user are potentially hazardous such that an unintentional activation is not desired. You can use this option to define that such actions have to be confirmed in a confirm dialogue.

Default: disabled

Function on double-click

If a computer is double-clicked in Veyon Master, a predefined function can be triggered. The usage of the functions remote control or remote view is conventional.

Default: <no function>

Computer Management

Always open on start
You can use this option to define that the computer management is opened upon program start by default. Default: disabled
Only show current room

As a default, the computer management lists all rooms in the configured network object directory. By activating this option you can assure that only the room the Master computer is based in is listed. This can increase lucidity especially in larger environments.

Default: disabled

Allow adding rooms manually
In conjunction with the option only show current room is can be additionally specified, that further rooms can be added to the computer management manually. If this option is activated, an additional Add Room button is shown that opens a dialogue with all available rooms.

Default: disabled

Hide local computer

In normal operation mode it is often not desired to display one’s own computer and activated room-wide activated function on one’s own computer as well (e.g. screen lock). Hiding a local computer can be activated through this option.

Default: disabled

Hide empty rooms

Under certain circumstanced the network object directory contains rooms without computers, for example due to specific LDAP filters. These empty rooms can be hid away from the computer management through this option.

Default: disabled

Hide filter field for computers

The filter field for searching computers can be hid through this option, to keep the user interface as simple as possible in small environments.

Default: disabled

Functions

With the help of the two lists in the Functions tab is can be defined which functions are available in Veyon Master. Single functions can therefore be deactivated if necessary, such that respective buttons and context menu entries are not displayed in Veyon Master. This may increase lucidity of the user interface if certain functions are not to be used anyway.

A function can be moved from one list to the other by marking and confirming the respective button with the arrow keys. A double-click has the same effect on a function.

Authentication

Authentication Methods

There are same-named options provided for the Authentication Methods described in chapter Configuration. After an option has been activated, the configuration of the respective authentication method is possible.

Keyfile authentication

You can use this option is activate keyfile authentication. The configuration can afterwards be done using the keyfile-assistant.

Default: disabled

Login authentication

You can use this option to activate login authentication. No further configuration is required and you can test the functionality directly after activation using the Test button.

Default: disabled

Key Management

Placeholder variables should be used for both base directories. A detailed description of possible values can be found in the Configuration Reference in section placeholder variables. Under Windows UNC paths <https://de.wikipedia.org/wiki/Uniform_Naming_Convention> _ can be used instead of absolute paths.

Base directory of the public key file

The keyfile-assistant places the role specific public key files in this directory after the keys have been generated or imported. On top of that the Veyon Service loads the respective public key file for authentication purposes from this directory.

Default: $GLOBALAPPDATA/keys/public

Base directory of the private key file

The keyfile-assistant places the role specific private key files in this directory after the keys have been generated. On top of that the Veyon Master loads the respective private key file to authenticate itself to clients from this directory.

Default: $GLOBALAPPDATA/keys/private

Access Control

Computer Access Control

Data backend
A data backend is required as a data base for access control. It provides users and groups as well as computers and rooms. Thereby you can choose between the standard backend and other plugin-specific backends such as LDAP. With a standard backend local users and groups as well as computers and rooms are loaded from the local configuration; see also section local data. If an LDAP connection is used, you should select the backend LDAP here.
Enable usage of domain groups

When using computer access control in combination with the local data: backend only the local system groups are available per default. By enabling this option all groups of the domain can be queried and used. This option is not enabled per default for performance reasons. In environments with a huge number of domain groups computer access control can take a long time. In such scenarios you should consider setting up the LDAP/AD integration and use the LDAP backend.

Default: disabled

Grant access to all authenticated users (default)
If the predefined authentication is sufficient (e.g. when using a keyfile authentication with restricted access to the key files), this option can be selected. In this mode no further access control is performed.
Restrict access to members of specific user groups
In this mode access to a computer is restricted to members of specific user groups. These authorized user groups can be configured in section authorized user groups for computer access.
Process access control rules
This mode allows for a detailed access control using user defined access control rules and offers maximum flexibility. However, its initial configuration is slightly more complicated such that one of the other two access control modes is recommended for initial testing.

Authorized User Groups for Computer Access

Configuration of this access control mode is straightforward. The left list contains all user groups provided by the data backend. By default these are all local user groups. If LDAP/AD Integration is configured, all LDAP user groups are shown. You can now select one or more groups and move them to the right list using the corresponding buttons between the two lists. All members of each group in the right list can access the computer. Remember to mirror the configuration to all computers.

Using the Test button in section Computer Access Control it can be checked, whether are specific user could potentially access a computer through the current group configuration.

Access Control Rules

Configuration of a rule set for access control including use cases are described in detail in chapter Rules Set for Computer Access.

Demo Server

Fine tuning can be done through the configuration page for the demo server to enhance performance in demo mode. These configurations should only be altered if performance is not satisfying or if only a small bandwith is available for transferring data.

Update interval
You can use this option to specify the interval between to screen updates. The smaller this interval is, the higher the update frequency and the smoother the screen transmission. However, a considerably low value might lead to higher CPU load and more network traffic.

Default: 100 ms

Key frame interval

During transmission of screen data only the parts of the screens that have actually changed are sent to the clients (incremental update) in order to minimize network load. These updates are carried out individually and asynchronously for each client. Thus, clients may not be running synchronously after a while depending on bandwidth and latency. To this end complete key frames are sent in equidistant intervals, such that after one key frame intervall all client will have a synchronized screen. The lower the value chosen, the higher the resulting CPU and network load will be.

Default: 10 sec

Memory limit

All screen update data is internally buffered by the demo server to be distributed to the clients later on. In order not to use too much memory space for the internal buffer due to incremental updates between two key frames, the value defined here serves as a limit. This limit is a soft-limit meaning that on exceeding it a key frame updated is tried (even if the key frame interval has not passed entirely), but the buffer still holds all data. Only if the specified limit is exceeded twofold (hard-limit) the buffer is reset. If there are frequent disruptions or lagging during a screen transmission, this value should be increased.

Default: 128 MB*

LDAP

All options that describe how to connect Veyon to an LDAP compatible server are explained in detail in chapter LDAP/AD integration.

Placeholder Variables for File Paths

Placeholder variables can be used with each operating system in both the Windows and Linux format $VARIABLE and %VARIABLE%.

Variable Expanded Path
APPDATA User specific directory for application data from Veyon, e.g. `...\User\AppData\Veyon under Windows or ~/.veyon under Linux
HOME, PROFILE Home directory of the signed in user, e.g. C:\Users\Admin under Windows or /home/admin under Linux
GLOBALAPPDATA System-wide directory for application data from Veyon, e.g. C:\ProgramData\Admin under Windows or /home/admin under Linux
TMP, TEMP User specific directory for temporary files, under Windows C:\Windows\Temp is used for the Veyon Service and /tmp under Linux

Program Parameters for Veyon Service

Dependening on the operating system under which Veyon is run, the Veyon Service can take various program parameters. The desired parameters have to be entered in the general service settings.

Parameter Operating System Meaning
-session <ID> <all> An integer between 0 and 99 can be used as optional session-ID, to have multiple instances of the Veyon Service running in different user sessions on the same computer. The session-ID is added to the number of the port configured in the network settings, such that each instace of the Veyon Service is working with different ports. You have to enter the absolute port (primary service port plus session-ID) together with the computer/IP-address, e.g. 192.168.2.3:11104.
<x11vnc-parameter> Linux The Veyon Service can take all parameters supported by the program x11vnc. For more information on this topic, please see the x11vnc manual <http://…> _.