snmpjs Documentation

• Features
• Getting Started
• What's Not Included
• Conformance
• More Information

Overview

var os = require('os');
var snmp = require('snmpjs');
var logger = require('bunyan');

var log = new logger({
    name: 'snmpd',
    level: 'info'
});

var agent = snmp.createAgent({
    log: log
});

agent.request({ oid: '.1.3.6.1.2.1.1.5', handler: function (prq) {
    var nodename = os.hostname();
    var val = snmp.data.createData({ type: 'OctetString',
        value: nodename });

    snmp.provider.readOnlyScalar(prq, val);
} });

agent.bind({ family: 'udp4', port: 161 });

snmpget -v 2c -c any localhost .1.3.6.1.2.1.1.5

Features

snmpjs allows you to implement agents, trap generators, and management applications that support the full range of SNMPv1 and SNMPv2c functionality. It is mostly compatible with all relevant standards -- see notes below -- and can also be extended to handle (and, optionally, to generate) SNMP messages that incorporate nonstandard data types and other deviations. Several pieces of standard MIB functionality are included along with a simple agent, but you can easily implement your own MIB subtrees or alternative agent. The library can also be used to incorporate SNMP functionality into other daemons; for example, to allow them to generate traps if a fault condition is detected.

Getting Started

npm install snmpjs

If you're new to SNMP, check out the gentle introduction. Otherwise, the API documentation is:

What's Not Included

Many pieces of functionality that would be useful are missing. The most noteworthy, some of which are really needed in order to create a complete suite of standard MIB providers, include:

• Agent: handling GetBulkRequests (*)
• Agent: error responses in the face of unparseable messages
• Agent: handling of excessively large responses (i.e., tooBig)
• Agent: access control; there is none at all presently (*)
• Agent: AgentX support, for aggregating disjoint MIBs on the same host and allowing multiple daemons to provide their own MIB subtrees
• Agent: introspection; i.e., an interface for providers to access information about the agent itself
• Agent: provider configuration; i.e., an interface for making agent configuration data available to MIB providers
• Other: More standard MIB providers
• Other: convenience functions for generating traps
• Management: command-line utilities for sending requests and displaying responses
• MIB: a MIB definition parser (to decorate the MIB for the benefit of management applications or for strict checking of provider responses)
• Provider: Convenience functions for implementing tabular providers; e.g., lexicographically-sorting data structures
• All: SNMPv3 support

(*) These items are really bugs that have practical solutions; they will be addressed in subsequent revisions of the software.

Conformance

In general, deviations from the relevant specifications are considered bugs and should have issues opened to track them. However, there is one notable exception, in which the design of snmpjs precludes an effective implementation of required behaviour. Specifically, SetRequests, clearly intended by the standard to be treated as an atomic transaction when multiple varbinds are present, are not handled that way. Instead, they are treated as multiple independent requests that can succeed or fail without affecting the others. If a failure occurs, the first varbind to cause a failure will be highlighted by the error_index field in the response, and the nature of the error will be specified by error_status. Subsequent varbinds may or may not have been assigned successfully. The commitFailed and undoFailed status codes are not used. This approach dramatically simplifies the implementation (the standard disdainfully yet correctly calls this "taking the easy way out"), and practical use of SNMP for control operations where such transactionality is required is exceedingly rare. If you are unfortunate enough to need it, however, you will need to select an agent that is not based on snmpjs.

More Information