Troubleshooting¶

"The switch did not answer." Check the address, that SNMP is enabled on the switch, that no firewall drops UDP port 161 between Home Assistant and the switch, and the community: with a wrong community, switches do not answer at all.

"The switch rejected the SNMPv3 user." User name, passwords and both protocols must match exactly what the switch has for the user. Some switches accept only certain password lengths or characters.

A port shows the wrong device, or many devices. Set up all your switches and turn LLDP on on each of them: a switch that is not set up, or that LLDP does not show, counts as a device, so everything behind it appears on the port it hangs on. Devices behind an access point or an unmanaged switch share that port.

A device is missing. Switches forget silent devices after a few minutes. It appears again once it sends something.

Entities are unavailable. The switch did not answer the last reading (see the first entry), or a port no longer exists on it. Entities of a port that is gone for good can be removed on the entity's page.

Received, sent and errors are missing. They are off by default: Settings, Devices & services, Managed Switch (SNMP), the switch, then the entities not shown, and enable the ones you want.

Received and sent stay unknown. They need the 64-bit counters (ifXTable), which SNMPv1 and some small switches do not offer.

Diagnostics. The entry's three dots, Download diagnostics: counts and structure of what the switch answers, without addresses, names or credentials. Attach it to an issue.

Debug logging. The entry's three dots, Enable debug logging; the loggers are custom_components.managed_switch, aiosnmpswitch and pysnmp. Read a debug log before you share it: pysnmp may log the requests it sends, and with SNMPv1 or v2c those carry the community.