Example scripts

SNMP is not simple (PySNMP implementation takes over 15K lines of Python code), but PySNMP tries to hide the complexities and let you carry out typical SNMP operations in a quick and intuitive way.

PySNMP offers high and low-level programming interfaces to deal with SNMP protocol.

The other dimension of differences in the PySNMP APIs is that there are two different SNMP implementations - the initial architecture (RFC1901 .. RFC1905) also known as SNMP v1 architecture and the redesigned variant (RFC3413 and others) – SNMPv3 architecture.

Note

The SNMP v1 architecture supports SNMP protocol versions 1 and 2c, while SNMP v3 architecture supports versions 1, 2c and 3. Whatever new amendments to the SNMP protocol may come up in the future, they will be implemented within the v3 model.

High-level SNMP

The high-level API (hlapi) is designed to be simple, concise and suitable for the most typical client-side operations. For that matter, only Command Generator and Notification Originator Applications are wrapped into a nearly one-line Python expression.

The hlapi interfaces come in several flavours: one synchronous and a bunch of asynchronous, adapted to work withing the event loops of popular asynchronous I/O frameworks.

The primary reason for maintaining high-level API over both v1arch and v3arch is performance - v3arch machinery is much more functional and complicated internally, that translates to being heavier on resources and therefore slower.

Low-level v3 architecture

Complete implementation of all official Standard SNMP Applications. It should let you implement any SNMP operation defined in the standard at the cost of working at a somewhat low level.

This API also comes in several transport varieties depending on I/O framework being used.

Low-level v1 architecture

In cases where performance is your top priority and you only need to work with SNMP v1 and v2c systems and you do not mind writing much more code, then there is a low-level API to SNMP v1/v2c PDU and PySNMP I/O engine. There’s practically no SNMP engine or SMI infrastructure involved in the operations of these almost wire-level interfaces. Although MIB services can still be used separately.

A packet-level API-based application typically manages both SNMP message building/parsing and network communication via one or more transports. It’s fully up to the application to handle failures on message and transport levels.

Using these examples

Before doing cut&paste of the code below into your Python interpreter, make sure to install pysnmp and its dependencies by running pip or easy_install:

# pip pysnmp

There’s a public, multilingual SNMP Command Responder and Notification Receiver configured at demo.snmplabs.com to let you run PySNMP examples scripts in a cut&paste fashion. If you wish to use your own SNMP Agent with these scripts, make sure to either configure your local snmpd and/or snmptrapd or use a valid address and SNMP credentials of your SNMP Agent in the examples to let them work.

Should you want to use a MIB to make SNMP operations more human-friendly, you are welcome to search for it and possibly download one from our public MIB repository. Alternatively, you can configure PySNMP to fetch and cache required MIBs from there automatically.

If you find your PySNMP application behaving unexpectedly, try to enable a /more or less verbose/ built-in PySNMP debugging by adding the following snippet of code at the beginning of your application:

from pysnmp import debug

# use specific flags or 'all' for full debugging
debug.setLogger(debug.Debug('dsp', 'msgproc', 'secmod'))

Then run your app and watch stderr. The Debug initializer enables debugging for a particular PySNMP subsystem, ‘all’ enables full debugging. More specific flags are:

  • io
  • dsp
  • msgproc
  • secmod
  • mibbuild
  • mibview
  • mibinstrum
  • acl
  • proxy
  • app

For more details on PySNMP programming model and interfaces, please refer to library documentation.