SNMP

SNMP brings the infrastructure layer into the same namespace as the process layer: switches, UPS units, PDUs, environmental monitors, printers, industrial routers. Anything with an agent.

Configuration

Field	Description
Name	Connection identifier.
Host	Agent IP or hostname.
Port	161 by default.
Version	1, 2c, or 3.
Timeout (ms)	Per-request timeout.
Retries	Retries before the request fails.
Max repetitions	GETBULK window for v2c/v3 walks. Higher is faster but produces larger responses.
Probe OID	The OID the connection test reads. 1.3.6.1.2.1.1.1.0 (sysDescr) is a safe universal choice.

v1 / v2c

Field	Notes
Community	The read community string.
Write community	Optional, for SET operations.

Community strings are transmitted in clear text. On any network you do not fully control, use v3.

v3 (USM)

Field	Values
Security level	noAuthNoPriv, authNoPriv, authPriv
Security name	The USM user name
Auth protocol	MD5, SHA, SHA-224/256/384/512
Auth key	The authentication passphrase
Priv protocol	DES, AES, AES-192/256
Priv key	The privacy passphrase
Context name	Optional SNMPv3 context

Keys are stored encrypted and never returned to the browser; the edit form shows only has_auth_key / has_priv_key presence flags.

Binding tags

Field	Notes
Address	The OID, dotted numeric (1.3.6.1.2.1.1.3.0). The data type is taken from the agent's reply and coerced to the tag's.
Poll Rate (ms)	How often the OID is read with an SNMP GET — 1000 by default, at least 100. OIDs sharing a rate are batched into one request. Infrastructure rarely needs faster than 30–60 s. SNMP has no subscription; traps arrive separately.

Browse an OID instead of typing it. New in 1.0.8 The button beside the address walks the agent from a start OID — prefilled from the address you are editing — and lists what it exposes, each with its value and type; picking one fills in the address and the data type. The walk runs only when you ask for it, since a walk can take up to a minute, and stops if you close the dialog. The address it writes is always the numeric OID: a symbolic name depends on which MIBs an installation happens to carry.

Remember the trailing .0 for scalar objects. 1.3.6.1.2.1.1.3 is the object; 1.3.6.1.2.1.1.3.0 is its single instance. Table columns are indexed instead — 1.3.6.1.2.1.2.2.1.10.3 is ifInOctets for interface 3.

Walking an agent

Walk in the connection's editor (needs View Connections) walks the agent's tree and returns each OID with its value and, where a MIB is loaded, its symbolic name. This is how you find out what a device actually exposes, rather than trusting a datasheet.

Vendor MIBs

Standard MIB-II is understood out of the box. Vendor MIBs turn 1.3.6.1.4.1.318.1.1.1.2.2.1.0 into upsAdvBatteryCapacity.

Action	Permission
List loaded MIBs	View Connections
Upload a MIB	Create Connection

Uploaded MIBs are compiled by an isolated child process, so a malformed vendor MIB — and they are frequently malformed — cannot crash the gateway. A MIB that fails to compile is rejected with its error; names simply fall back to numeric OIDs.

Traps

Devices push asynchronous notifications (a UPS switching to battery, a link going down). QUBIQ can listen on UDP 162; the listener is opt-in and off by default.

Received traps are resolved against the loaded MIBs — so you see linkDown, not 1.3.6.1.6.3.1.1.5.3 — and kept in a rolling buffer for the operator feed.

The trap feed is in the connection's editor (needs View Connections).

Traps are fire-and-forget

SNMP traps are unacknowledged UDP. A trap sent while QUBIQ is restarting is gone. Never rely on traps alone for a condition that matters — poll the underlying value and accept the trap for low latency.

Typical monitoring set

What	OID	Why
Uptime	1.3.6.1.2.1.1.3.0	A reset counter means the device rebooted
Interface operational status	1.3.6.1.2.1.2.2.1.8.<if>	Link up/down — a good on_boolean alarm
Interface in/out octets	1.3.6.1.2.1.2.2.1.10/16.<if>	Throughput; counters, so trend the rate
Interface errors	1.3.6.1.2.1.2.2.1.14/20.<if>	Rising errors precede a failing link
UPS battery capacity, on-battery status	vendor MIB	Facility power
Temperature	vendor MIB	Cabinet/environment

Counters wrap. Alarm on the rate of change, not the raw counter, using a pipeline or a derived tag.

One dead agent, one slow connection Changed in 1.0.7

All SNMP connections share one worker, and before 1.0.7 an unreachable agent could hold the others up in three ways:

• A walk blocked everyone for up to a minute. Requests were handled one at a time across every connection, and a walk is allowed sixty seconds. While one ran against a slow or dead agent, every other connection's check, read and write waited — and each caller, having timed out, reported the worker unavailable. Requests for different agents are now handled side by side. One agent still gets one request at a time.
• A dead agent cost a full retry budget per chunk. A poll of many OIDs is sent in chunks, and after a transport failure the driver kept sending the remaining chunks, paying Timeout × Retries for each against an agent it already knew was not answering. The rest of the cycle is now marked failed at once, so a dead agent costs one chunk's timeout per cycle rather than one per chunk, and the next attempt is paced by the backoff.
• Changing one connection's configuration stalled the rest while its poller wound down. That wait is now that connection's alone.

A connection whose configuration is changed also no longer leaves its old UDP association open for the life of the process.

Troubleshooting

Symptom	Check
Timeout on every request	Agent not enabled, firewall on UDP 161, or an ACL restricting source addresses.
Works with snmpwalk, not QUBIQ	Source-IP ACL on the agent — add the QUBIQ host.
v3 authentication fails	Security level must match the agent exactly; authPriv with only an auth key configured will fail.
Some OIDs return nothing	Missing .0 on a scalar, or the object is not implemented by that device.
Names show as numeric OIDs	The vendor MIB is not uploaded, or failed to compile.
Walk is very slow	Reduce max repetitions, or walk a subtree instead of the whole agent.
Other SNMP connections report the worker unavailable during a walk	Fixed in 1.0.7 — see one dead agent.

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