louislam/uptime-kuma · warning · Error

The SNMP query returned that no instance exists for OID ${mo

Error message

The SNMP query returned that no instance exists for OID ${monitor.snmpOid}

What it means

Thrown when varbinds[0].type equals snmp.ObjectType.NoSuchInstance. NoSuchInstance is a per-object error indicator defined by RFC 3416: the agent understood the GetRequest and the variable binding syntax, but no managed object instance exists at the requested OID. It is distinct from a transport error or a noSuchObject (wrong type/leaf) response.

Source

Thrown at server/monitor-types/snmp.js:57

                throw new Error(`Error creating SNMP session: ${error.message}`);
            });

            const varbinds = await new Promise((resolve, reject) => {
                session.get([monitor.snmpOid], (error, varbinds) => {
                    error ? reject(error) : resolve(varbinds);
                });
            });
            log.debug(
                this.name,
                `SNMP: Received varbinds (Type: ${snmp.ObjectType[varbinds[0].type]} Value: ${varbinds[0].value})`
            );

            if (varbinds.length === 0) {
                throw new Error(`No varbinds returned from SNMP session (OID: ${monitor.snmpOid})`);
            }

            if (varbinds[0].type === snmp.ObjectType.NoSuchInstance) {
                throw new Error(`The SNMP query returned that no instance exists for OID ${monitor.snmpOid}`);
            }

            // We restrict querying to one OID per monitor, therefore `varbinds[0]` will always contain the value we're interested in.
            const value = varbinds[0].value;

            const { status, response } = await evaluateJsonQuery(
                value,
                monitor.jsonPath,
                monitor.jsonPathOperator,
                monitor.expectedValue
            );

            if (status) {
                heartbeat.status = UP;
                heartbeat.msg = `JSON query passes (comparing ${response} ${monitor.jsonPathOperator} ${monitor.expectedValue})`;
            } else {
                throw new Error(
                    `JSON query does not pass (comparing ${response} ${monitor.jsonPathOperator} ${monitor.expectedValue})`

View on GitHub (pinned to 6b5ea01557)

Solutions

Use snmpwalk/snmpget externally to find a concrete instance OID for this device, then paste the full leaf-with-index OID into monitor.snmpOid.
If the OID is a table column, append the relevant row index (e.g. interface index) to select a real instance.
Confirm the device model/firmware actually implements the MIB at that OID.
Switch to a known-good scalar OID (e.g. sysUpTime.0 = 1.3.6.1.2.1.1.3.0) to verify the path before reintroducing the target OID.

Defensive patterns

Strategy: validation

Validate before calling

const snmp = require("net-snmp");
function assertInstancePresent(varbind, oid) {
  if (varbind.type === snmp.ObjectType.NoSuchInstance) {
    throw new Error(`No instance for OID ${oid}`);
  }
  return varbind;
}

Type guard

function isInstancePresent(varbind) {
  return varbind && varbind.type !== snmp.ObjectType.NoSuchInstance && varbind.type !== snmp.ObjectType.NoSuchObject;
}

Try / catch

if (!isInstancePresent(varbinds[0])) { heartbeat.status = DOWN; heartbeat.msg = `No instance for ${monitor.snmpOid}`; return; }

Prevention

Always query a concrete leaf OID with its index suffix.
Walk the MIB once to confirm the instance exists before pinning the monitor OID.
Prefer scalar OIDs ending in .0 for simple health checks.

When it happens

Trigger: Triggered by session.get() when the OID names a scalar/column that the agent implements but has no instance for, or when querying a table column OID without a row index suffix. Also occurs when the instance has been deleted or is not yet populated on the device.

Common situations: Querying a table column OID directly (e.g. 1.3.6.1.2.1.2.2.1.10) without appending .ifIndex; querying an interface counter OID for an interface that no longer exists; pointing at an OID from a different device model where that MIB subtree is absent; stale documentation referencing an OID that the firmware revision no longer exposes.

Related errors

AI-assisted analysis of louislam/uptime-kuma@6b5ea01557 (2026-08-12). Data as JSON: /api/errors/3a55f6bc8bf35db5. Report an issue: GitHub.