apache/seatunnel · error · IOException

SNMP request timed out for agent {host}:{port}

Error message

SNMP request timed out for agent {host}:{port}

What it means

Snmp4jClient.get() issues an SNMP GET for the configured OIDs. If snmp.send() returns null or a ResponseEvent with a null response, the agent did not answer within the timeout/retries and this IOException is thrown. It means the poll could not be completed, not that the OIDs are missing.

Source

Thrown at seatunnel-connectors-v2/connector-snmp/src/main/java/org/apache/seatunnel/connectors/seatunnel/snmp/source/Snmp4jClient.java:67

        this.target = buildTarget(config);
        try {
            snmp.listen();
        } catch (IOException e) {
            try {
                snmp.close();
            } catch (IOException closeException) {
                e.addSuppressed(closeException);
            }
            throw e;
        }
        this.snmp = snmp;
    }

    @Override
    public List<SnmpRecord> get(List<OID> oids) throws IOException {
        ResponseEvent event = snmp.send(buildGetRequest(oids), target);
        if (event == null || event.getResponse() == null) {
            throw new IOException(
                    "SNMP request timed out for agent "
                            + config.getHost()
                            + ":"
                            + config.getPort());
        }

        PDU response = event.getResponse();
        if (response.getErrorStatus() != PDU.noError) {
            throw new IOException(
                    "SNMP agent returned error status "
                            + response.getErrorStatus()
                            + " ("
                            + response.getErrorStatusText()
                            + ") at index "
                            + response.getErrorIndex());
        }
        return extractRecords(response);
    }

View on GitHub (pinned to cf67b549a7)

Solutions

1. Verify host/port and test manually: snmpget -v2c -c <community> <host> <oid>.
2. Correct the community string/SNMPv3 credentials — agents silently discard unauthorized GETs.
3. Raise timeout and retry counts in the target built from the source config.
4. Check network path (firewall, routing) from the SeaTunnel worker to the agent.
5. Reduce OID batch size if the agent struggles with large GET PDUs.

Example fix

// before
timeout = 500ms, retries = 1 on a WAN link
// after
timeout = 5000ms, retries = 3 in SnmpSourceConfig target settings

// pre-flight probe before the source starts
String out = snmpCli("snmpget -v2c -c " + community + " -t 5 -r 3 " + host + " " + firstOid);
if (out == null || out.isEmpty()) throw new IllegalStateException("SNMP agent not answering");

try {
    records = client.get(oids);
} catch (IOException e) {
    if (attempt < MAX_RETRIES) { backoff(); retry(); } else throw new SourceUnavailableException(host, e);
}

When it happens

Trigger: Calling get(List<OID>) when the GET PDU times out (event==null or event.getResponse()==null) against agent host:port.

Common situations: Agent offline or wrong IP/port in source config; firewall blocks UDP 161 from the worker; community string wrong (agent drops silently); timeout too short for large OID batches or busy agents; IPv6/IPv4 mismatch.

Understand the failure class

Background: Request timed out: what client-side request timeouts mean across libraries (Request timed out, TIMED_OUT, APITimeoutError) — this error's family across 39 libraries.

• Timeouts: ETIMEDOUT, deadlines, and hung requests — what actually expires when a request times out.

Related errors

• SNMP SET request timed out for agent {host}:{port}
• Option 'visibility_timeout_seconds' must be between 1 and 60
• Timed out after <actualSeconds> seconds while waiting to con
• SNMP source timeout_millis must be greater than 0
• SNMP agent returned error status {errorStatus} ({errorStatus

AI-assisted analysis of apache/seatunnel@cf67b549a7 (2026-09-10). Data as JSON: /api/errors/141dd5bcea5425cd. Report an issue: GitHub.