You would probably have the default ACL applied which should by default permit all IPv4 inbound and outbound traffic.
Security groups are stateful so any outbound traffic sent from an instance is allowed a return response regardless of the inbound rules you have defined. Responses to allowed inbound traffic are also not blocked regardless of any outbound rules applied.
If you created and applied the security group then you will need to add the necessary inbound rules. By default this security group includes an outbound rule that permits all outgoing traffic.
The default security group allows all inbound traffic (and by default all outbound traffic) unless additional rules have been applied. If you are using the default security group I would suggest removing any added rules then attempting another demo connection to see if that works. I’m assuming the demo port is 11400.
@davidemorellato There are two components involved: Veyon Service (which you can control and observe via systemctl) and Veyon Server. The Veyon Service is responsible for starting Veyon Server instances for user sessions (if multi session mode is enabled, one instance for each session is started, otherwise only for instance for the most-recently opened session is started and previous instances are stopped). So what seems to happen in your case is that either the Veyon Server instances are not started at all for some reason or crash during startup or normal operation.
For further troubleshooting, first please update to the latest version available in our PPA (4.5.3-2) which contains additional fixes regarding session management. If it does not help, set the log level in Veyon Configurator to Debug, reboot, login and paste the output of /tmp/VeyonServ*.log here so we can examine it in detail.
The VariantArrayMessage messages are interesting. They seem to indicate some kind of protocol incompatibility issue between master and client computers. Did you compile Veyon on your own on Linux Mint? If so, which version of Qt 5 is installed?
Regarding the screenshot warning: thanks for pointing that out! I just fixed the issue which will also be part of the upcoming 4.5.3 release.
@grossell Using Veyon with other credential providers is untested and not supported (even though it might work to a certain degree). Are the GCPW user groups listed in the corresponding configuration dialogs? Alternatively you can switch to key file authentication and set up access permissions to the private key file(s) accordingly.
Can you post a screenshot of the Master configuration page where you disabled some features? At a quick test I was unable to reproduce the behaviour you described.
Please note that you can't delete websites/programs that you configured statically in Veyon Configurator. Only custom websites/programs opened by teachers and added after checking the "Remember" checkbox can be removed afterwards using the delete key.
Currently you can only block Internet access completely using the Internet Access Control add-on. However it allows configuring exceptions (statically) such as local or intranet sites so these sites stay reachable while the Internet access is blocked. In a future release this year, we'll add a blacklisting features, so teachers can easily block the access to specific sites, e.g. video platforms.