Error after changing port

[Andrei]

The error message in the log indicates permission issue. The reason is that it is necessary root privilege's to use ports below 1024.

Some references:

Raspberry Pi and UDP?

The error is exactly what it says: If you want to use a port number < 1024, you need to run as root. We generally recommend not to run as root, so if you can, pick a port higher than 1024.

Problems to open port 162 (SNMP-TRAP)

I want to use node-red-contrib-snmp-trap-listener to receive traps via snmp, on port 162, but I get this error "can't open port: 162". I have the same problem with node-red-contrib-syslog, which uses port 514. I have read that only the root user can open privileged ports (1-1024). Is there any way for node-red to open privileged ports without error? Best regards

Modbus TCP Server on port 502

Not to bump an old thread, but for anyone who comes searching, the most likely culprit is needing root access to listen on a port less than 1024, assuming you're running Node-RED on a Linux device.