Internet-Security.com TCP port 1911 details

TCP port 1911 is primarily used by the Tridium Niagara Framework’s Fox protocol (unencrypted), for communication between Niagara Workbench/Supervisors and JACE controllers; newer deployments often use 4911 for the TLS-secured Fox service.
Real-world examples include Niagara-based building automation systems such as Honeywell/Tridium VYKON JACE controllers, Johnson Controls Facility Explorer (FX) Niagara controllers, Schneider Electric/TAC I/A Series (Niagara-based) controllers, and Distech Controls EC‑BOS devices.
It is widely deployed in HVAC, lighting, and access-control integrations where Niagara stations communicate and exchange data/configuration over Fox on 1911.
Security note: Port 1911 has been frequently targeted; historical Niagara vulnerabilities (e.g., directory traversal, authentication/credential disclosure issues) and misconfigurations have been exploited in the wild, and attackers routinely scan for exposed Fox services.

TCP 1911