snmp — Simple Network Management Protocol

This library implements the Simple Network Management Protocol (SNMP). In spite of it’s name, SNMP has a reputation for being complicated and confusing. This library is an attempt to put the “simple” back in SNMP.

An SNMP manager is a machine or an application that generates and sends SNMP requests to other machines in a network. An SNMP agent, running on one of these other machines, processes each request, and sends back a response. There are four available request types: Get, GetNext, GetBulk (as of SNMPv2), and Set. The Get* request types are generally used to query information without affecting the state of the machine, whereas the Set request is generally meant to update a machine’s configuration.

Each request contains a list of “variable bindings,” (varbinds), which is a fancy term for a name/value pair. The “name” of a varbind is formatted as an ASN.1 Object Identifier (OID), such as "1.3.6.1.2.1.1.1.0". Once you know the name, data type, and meaning of a variable, the protocol is quite simple to use. The hard part is determining the exact OID that corresponds to the variable you want. This is probably where SNMP gets its reputation for being complicated and confusing.

The Manager Interface (Simplified)

The Manager interface defines a method for each of the four request types (listed above). Each Manager object communicates with a single remote machine, so that you, the caller, only need to configure the IP address once, rather than including it in the argument list of every request. This section documents the essential arguments and behavior of this interface; The Manager Interface section documents the interface in full.

Note that SimplifiedSnmpManager is an abstract interface specification; there is no class with that name in the snmp library. To instantiate a concrete Manager object, you must use the Engine.Manager() factory method.

class SimplifiedSnmpManager
get(*oids: OID | str, timeout: float = 10.0) → VarBindList

This method sends an SNMP Get request and awaits the response. The positional arguments give the OIDs for the request. Each argument may be either a string, formatted like ".1.3.6.1.2.1.1.1.0" or "1.3.6.1.2.1.1.1.0" (i.e. with or without the leading dot), or an snmp.smi.OID object. The method will block until a response is received, up to a maximum of timeout seconds.

When successful, the call returns the variable bindings as a snmp.smi.VarBindList.

vblist = manager.get("1.3.6.1.2.1.1.1.0", "1.3.6.1.2.1.1.3.0")

# VarBindList -> VarBind -> OctetString -> bytes -> str
descr = vblist[0].value.data.decode()

# VarBindList -> VarBind -> TimeTicks -> int -> float
uptime = vblist[1].value.value / 100

print(f"System Description: \"{descr}\"")
print(f"System Up-Time: {uptime} seconds")

This method raises an ErrorResponse exception when it receives a response with a non-zero error-status, indicating that the agent was able to understand the request, but not able to fulfill it. In the case of a "noSuchName" error, the call raises the more specific NoSuchName exception, a sub-class of ErrorResponse, so that you may handle it in a dedicated except block.

If the Manager does not receive a response within timeout seconds, it will raise a Timeout exception.

In some cases, this method may raise an Exception type other than those listed here. See SnmpManager.get() for more details.

oid = "1.3.6.1.2.1.1.1.0"

try:
    vblist = manager.get(oid)
except NoSuchName:
    print(f"This machine has no value for {oid}")
except ErrorResponse as err:
    print(f"Error: {err.status.name}")
except Timeout:
    print("The request timed out!")
except Exception as err:
    print(err)
getBulk(*oids: OID | str, nonRepeaters: int = 0, maxRepetitions: int = 1, timeout: float = 10.0, j) → VarBindList

Send an SNMP GetBulk request and await the response. The behavior of this method is the same as the get() method, aside from the request type, and the addition of the nonRepeaters and maxRepetitions parameters.

For an explanation of this request type, see SnmpManager.getBulk().

getNext(*oids: OID | str, timeout: float = 10.0) → VarBindList

Send an SNMP GetNext request, and await the response. The behavior of this method is the same as the get() method, aside from the request type.

set(*varbinds: VarBind | tuple, timeout: float = 10.0) → VarBindList

Send an SNMP Set request, and await the response. The behavior of this method is the same as the get() method, aside from the request type and the format of the positional arguments.

While the other request methods take OIDs for the positional arguments, this method requires a value to go along with each OID. The varbinds argument(s) may be either a (name, value) tuple, or a VarBind. The name element accepts either a str or an OID, just like the *oids argument list to the get() method. The value element must be an instance of one of the classes defined in snmp.smi.

name = "1.3.6.1.2.1.1.1.0"
value = OctetString(b"New system description")
vblist = manager.set((name, value))

Package Structure

Each of the following sections lists the variables that are defined as a result of the given import statement.

Essential Features

The top-level snmp module exports all the essential data types and named constants needed for a basic SNMP application.

from snmp import *

Engine Class:

Named Constants:

Enumerations:

Exception Types:

SMI Classes (from snmp.smi):

SNMP Data Types

from snmp.smi import *

Primitive Types:

Integer Types:

OctetString Types:

Null Types:

Named Constants:

Variable Bindings:

Authentication Protocols

from snmp.security.usm.auth import *

Privacy Protocols

from snmp.security.usm.priv import *