TCP 4911
Synopsis
- TCP port 4911 is the default port for Tridium Niagara 4’s secure Fox protocol (“foxs”), used for encrypted communications between Niagara stations and clients.
- Real-world deployments include Tridium JACE-8000 controllers and Niagara Supervisors, as well as OEM-branded systems like Honeywell WEBs-N4, Johnson Controls Facility Explorer (FX), Distech Controls EC-Net 4, and VYKON.
- Niagara Workbench clients connect to Niagara 4 stations over TCP 4911 for management and engineering tasks.
- Building automation deployments using BACnet/Modbus via Niagara commonly expose this port on supervisory controllers.
- Security note: Port 4911 has been a target in ICS/OT attacks, with prior Niagara 4/AX Fox-related vulnerabilities and misconfigurations (e.g., default credentials/certificates) enabling reconnaissance or unauthorized access when exposed to the internet.
Observed activity
Last 30 days
Detailed chart