Demo mode not working on EC2 instances


  • Hello Veyon Community,

    I created a virtual network with AWS EC2 instances for online training in our company. Viewing and controlling clients with the master works flawlessly, but sharing the screen via demo mode doesn't work.
    The demo seems to fail silently (the master shows the "end demo" option after starting a demo even though the clients don't show any indication something changed).

    My setup involves:
    3x EC2 ( With network security configured to open the ports: 11100, 11300, 11400 + VNC port)
    OS: Windows Server 2016 Datacenter
    Veyon: 4.5.2.0
    External VNC: UltraVNC 1.3.2a

    I already tried downgrading to 4.3 as it seemed to work for the user here: https://veyon.nodebb.com/topic/1161/4-4-2-downgrade-options-crashes-master-and-clients-no-demo

    But couldn't get the Demo mode working there either.
    Any help is much appreciated.


  • @marcel

    So you are using security groups but no custom network ACL, correct?


  • @itguy Yes I'm using security groups. No ACLs as far as I'm aware. I normally don't work on setting up networks or anything AWS-related.


  • @marcel

    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.