Enforce client device authentication in the configuration of the OPC UA server. Configure a proper “SecurityPolicy” for OPC UA Server ( Automation Help https://help.br-automation.com/#/en/4/communication/opcua/runtime/opcua_config_security.html ) and select a “CertificateStore configuration” which has “Validate SSL communication partner” set to “on” ( Automation Help https://help.br-automation.com/#/en/4/access_and_security%2Fssl%2Fssl_configuration.html ). Limit access to the OPC UA Server (default 4840/tcp) to IP addresses or IP subnets which are running instances of impacted mapp components and legitime OPC UA clients using the B&R Automation Runtime host-based firewall. Ensure only trusted personal is able to access devices with the specified IP (range) and enforce strict authentication on these devices. Please be aware that B&R Automation Runtime and its services (like mapp components) are not intended to be directly connected to the internet at any time. Customers are advised to use the host-based firewall as well as an external control network firewall to limit access to each service running at B&R Automation Runtime. Additionally, consider granting access from the outside of the control network only to specific timeframes (e.g. for maintenance). mapp View For customers only using the OPC UA Server for their mapp View Visualization, block all incoming traffic to the OPC UA Server (default port 4840/tcp) using the B&R Automation Runtime host-based firewall. Blocking external traffic on the OPC UA Server has no impact on the functionality of mapp View.