SNMP library for Python

PySNMP is a cross-platform, pure-Python SNMP engine implementation. It features fully-functional SNMP engine capable to act in Agent/Manager/Proxy roles, talking SNMP v1/v2c/v3 protocol versions over IPv4/IPv6 and other network transports.

Despite its name, SNMP is not really a simple protocol. For instance its third version introduces complex and open-ended security framework, multilingual capabilities, remote configuration and other features. PySNMP implementation closely follows intricate system details and features bringing most possible power and flexibility to its users.

Note

snmpclitools, which older documentation described as shipping with PySNMP, is a separate project and is not part of this one. The release on PyPI depends on the pysnmp distribution, which is a different fork from a different repository – installing it beside pysnmplib puts two SNMP engines in one environment.

PySNMP is free and open-source software, distributed under a 2-clause BSD-style license. The source is at pysnmp/pysnmp.

Three other projects are maintained alongside it, and the organization site describes how they fit together:

• the MIB distribution, which supplies the module definitions an engine resolves names against;

• pysmi, the MIB compiler, installed with the compile extra;

• pyasn1, the ASN.1 codec underneath both, installed with PySNMP itself.

PySNMP library development has been initially sponsored by a PSF grant.

Quick start

You already know something about SNMP and have no courage to dive into this implementation? Try out quick start page!

• Quick start
  • Fetch SNMP variable
  • Send SNMP TRAP

Documentation

• Documentation
  • SNMP history
  • SNMP design
  • PySNMP architecture
  • Common operations
• Library reference
  • Synchronous SNMP
  • Asynchronous: asyncio
  • SNMP Engine
  • Security Parameters
  • SNMP Context
  • MIB services
  • SNMP base types
• Errors and supporting types
  • Exceptions
  • Warnings
  • Return types
  • Transport
  • MIB services
  • Synchronous command generators
• Breaking Changes
  • MIB instrumentation takes (varBind, **context)
  • The high-level API is snake_case, and camelCase is deprecated
  • Python 3.10 is the minimum supported version
  • asyncore and asynsock have been removed
  • pyasn1.compat.octets is no longer used
  • pycryptodomex imports are now resolved lazily
  • Weak-crypto warnings are emitted at configuration time
  • pysmi API calls use snake_case
  • Corrected behaviour that may change results
• Security Considerations
  • Recommended configuration
  • Protocol status
  • Configuration warnings
  • Turning SNMPv1 and SNMPv2c off
  • Cipher backend
• SMI table construction and cell addressing
  • Addressing table cells
  • Optional columns during row activation
  • Choosing clone or subtype
• Serving values an agent has to wait for
  • A controller that waits
  • SET atomicity is the controller’s, and always was
  • What stays true across the wait
  • What this does not cover
  • What it costs
• Device details report
  • Asynchronous use
  • Synchronous use
  • API reference
• Diffie-Hellman USM key change
  • How the exchange works
  • Changing a key
  • Using the result
  • When the SET is the step that fails
  • Finding the row
  • What is supported
  • Interoperability
  • API reference
• MIB instance generation tools
  • IANA Private Enterprise Numbers
  • Instances from an ASN.1 MIB
• Loading MIBs from a corpus
  • Nothing changes unless you ask
  • Why you might want one
  • Using one
  • Several corpora at once
  • Which copy answered
  • What was passed over
  • Resolving a trap OID without a compiler
  • What a corpus does not carry
  • How a module is built
  • Version gating
  • Where a module came from
• MIB module loader contract
  • Versioning
  • Contract v1
  • What is deliberately not in the contract
  • For generator authors
• Logging and tracing contract
  • The rule
  • What things cost
  • The budget, by granularity
  • Two audiences, two mechanisms
  • Rules for library code
  • A cautionary tale
  • How to measure a change here
• Codec benchmark
  • Why there is one
  • Running it
  • What it measures
  • Findings
  • What it does not measure

Examples

• Example scripts
  • High-level SNMP
  • Native SNMP API
  • Packet-level SNMP
  • Low-level MIB access
  • Using these examples

Download

Best way is usually to

$ pip install pysnmplib

If that does not work for you for some reason, you might need to read the following page.

• Download PySNMP

License

• License

FAQ

• FAQ
  • Getting peer address information
  • How to implement MIB at the Agent
  • Ignored SNMP packets
  • Listening on multiple network interfaces
  • Garbaged SNMP values (apps)
  • Garbaged SNMP values (tools)
  • Dealing with the “OID not increasing” error
  • How to pass MIB to the Manager
  • Resolve response values at MIB
  • SNMP data constraints verification error
  • Walking whole MIB

Further development

The changelog is generated from the commit history at release time. The narrative history of the project through 5.x is kept separately.

• Changelog
• Historical changelog

How changes reach a released version — the branches, the commit-message conventions, what CI runs and how a release is cut — is documented here.

• Continuous integration and releases
  • Branches
  • Commit messages
  • What runs on a pull request
  • The test matrix
  • Cutting a release
  • Keeping next and main in step
  • Reaching PyPI
  • Troubleshooting

Our development plans and new features we consider for eventual implementation are collected in the following section.

• Further development
  • PySNMP library
  • Stand-alone PySNMP-based tools

Contact

In case of questions or troubles using PySNMP, please open up an issue at GitHub or ask at Stack Overflow .