Agent-side MIB implementations¶
Implementing scalar MIB objects¶
Listen and respond to SNMP GET/SET/GETNEXT/GETBULK queries with the following options:
- SNMPv2c
- with SNMP community “public”
- serving custom Managed Object Instance defined within this script
- allow read access only to the subtree where the custom MIB object resides
- over IPv4/UDP, listening at 127.0.0.1:161
The following Net-SNMP commands will walk this Agent:
$ snmpwalk -v2c -c public 127.0.0.1 .1.3.6
import sys
from pysnmp.entity import engine, config
from pysnmp.entity.rfc3413 import cmdrsp, context
from pysnmp.carrier.asyncore.dgram import udp
from pysnmp.proto.api import v2c
# Create SNMP engine
snmpEngine = engine.SnmpEngine()
# Transport setup
# UDP over IPv4
config.addTransport(
snmpEngine,
udp.domainName,
udp.UdpTransport().openServerMode(('127.0.0.1', 161))
)
# SNMPv2c setup
# SecurityName <-> CommunityName mapping.
config.addV1System(snmpEngine, 'my-area', 'public')
# Allow read MIB access for this user / securityModels at VACM
config.addVacmUser(snmpEngine, 2, 'my-area', 'noAuthNoPriv', (1,3,6,5))
# Create an SNMP context
snmpContext = context.SnmpContext(snmpEngine)
# --- create custom Managed Object Instance ---
mibBuilder = snmpContext.getMibInstrum().getMibBuilder()
MibScalar, MibScalarInstance = mibBuilder.importSymbols(
'SNMPv2-SMI', 'MibScalar', 'MibScalarInstance'
)
class MyStaticMibScalarInstance(MibScalarInstance):
def getValue(self, name, idx):
return self.getSyntax().clone(
'Python %s running on a %s platform' % (sys.version, sys.platform)
)
mibBuilder.exportSymbols(
'__MY_MIB', MibScalar((1,3,6,5,1), v2c.OctetString()),
MyStaticMibScalarInstance((1,3,6,5,1), (0,), v2c.OctetString())
)
# --- end of Managed Object Instance initialization ----
# Register SNMP Applications at the SNMP engine for particular SNMP context
cmdrsp.GetCommandResponder(snmpEngine, snmpContext)
cmdrsp.NextCommandResponder(snmpEngine, snmpContext)
cmdrsp.BulkCommandResponder(snmpEngine, snmpContext)
# Register an imaginary never-ending job to keep I/O dispatcher running forever
snmpEngine.transportDispatcher.jobStarted(1)
# Run I/O dispatcher which would receive queries and send responses
try:
snmpEngine.transportDispatcher.runDispatcher()
except:
snmpEngine.transportDispatcher.closeDispatcher()
raise
Download
script.
Implementing conceptual table¶
Listen and respond to SNMP GET/SET/GETNEXT/GETBULK queries with the following options:
- SNMPv2c
- with SNMP community “public”
- define a simple SNMP Table within a newly created EXAMPLE-MIB
- pre-populate SNMP Table with a single row of values
- allow read access only to the subtree where example SNMP Table resides
- over IPv4/UDP, listening at 127.0.0.1:161
The following Net-SNMP commands will populate and walk a table:
$ snmpset -v2c -c public 127.0.0.1 1.3.6.6.1.5.2.97.98.99 s “my value”
$ snmpset -v2c -c public 127.0.0.1 1.3.6.6.1.5.4.97.98.99 i 4
$ snmpwalk -v2c -c public 127.0.0.1 1.3.6
...while the following command will destroy the same row
$ snmpset -v2c -c public 127.0.0.1 1.3.6.6.1.5.4.97.98.99 i 6
$ snmpwalk -v2c -c public 127.0.0.1 1.3.6
from pysnmp.entity import engine, config
from pysnmp.entity.rfc3413 import cmdrsp, context
from pysnmp.carrier.asyncore.dgram import udp
from pysnmp.proto.api import v2c
# Create SNMP engine
snmpEngine = engine.SnmpEngine()
# Transport setup
# UDP over IPv4
config.addTransport(
snmpEngine,
udp.domainName,
udp.UdpTransport().openServerMode(('127.0.0.1', 161))
)
# SNMPv2c setup
# SecurityName <-> CommunityName mapping.
config.addV1System(snmpEngine, 'my-area', 'public')
# Allow read MIB access for this user / securityModels at VACM
config.addVacmUser(snmpEngine, 2, 'my-area', 'noAuthNoPriv', (1,3,6,6), (1,3,6,6))
# Create an SNMP context
snmpContext = context.SnmpContext(snmpEngine)
# --- define custom SNMP Table within a newly defined EXAMPLE-MIB ---
mibBuilder = snmpContext.getMibInstrum().getMibBuilder()
( MibTable,
MibTableRow,
MibTableColumn,
MibScalarInstance ) = mibBuilder.importSymbols(
'SNMPv2-SMI',
'MibTable',
'MibTableRow',
'MibTableColumn',
'MibScalarInstance'
)
RowStatus, = mibBuilder.importSymbols('SNMPv2-TC', 'RowStatus')
mibBuilder.exportSymbols(
'__EXAMPLE-MIB',
# table object
exampleTable=MibTable((1,3,6,6,1)).setMaxAccess('readcreate'),
# table row object, also carries references to table indices
exampleTableEntry=MibTableRow((1,3,6,6,1,5)).setMaxAccess('readcreate').setIndexNames((0, '__EXAMPLE-MIB', 'exampleTableColumn1')),
# table column: string index
exampleTableColumn1=MibTableColumn((1,3,6,6,1,5,1), v2c.OctetString()).setMaxAccess('readcreate'),
# table column: string value
exampleTableColumn2=MibTableColumn((1,3,6,6,1,5,2), v2c.OctetString()).setMaxAccess('readcreate'),
# table column: integer value with default
exampleTableColumn3=MibTableColumn((1,3,6,6,1,5,3), v2c.Integer32(123)).setMaxAccess('readcreate'),
# table column: row status
exampleTableStatus=MibTableColumn((1,3,6,6,1,5,4), RowStatus('notExists')).setMaxAccess('readcreate')
)
# --- end of custom SNMP table definition, empty table now exists ---
# --- populate custom SNMP table with one row ---
( exampleTableEntry,
exampleTableColumn2,
exampleTableColumn3,
exampleTableStatus ) = mibBuilder.importSymbols(
'__EXAMPLE-MIB',
'exampleTableEntry',
'exampleTableColumn2',
'exampleTableColumn3',
'exampleTableStatus'
)
rowInstanceId = exampleTableEntry.getInstIdFromIndices('example record one')
mibInstrumentation = snmpContext.getMibInstrum()
mibInstrumentation.writeVars(
( (exampleTableColumn2.name+rowInstanceId, 'my string value'),
(exampleTableColumn3.name+rowInstanceId, 123456),
(exampleTableStatus.name+rowInstanceId, 'createAndGo') )
)
# --- end of SNMP table population ---
# Register SNMP Applications at the SNMP engine for particular SNMP context
cmdrsp.GetCommandResponder(snmpEngine, snmpContext)
cmdrsp.SetCommandResponder(snmpEngine, snmpContext)
cmdrsp.NextCommandResponder(snmpEngine, snmpContext)
cmdrsp.BulkCommandResponder(snmpEngine, snmpContext)
# Register an imaginary never-ending job to keep I/O dispatcher running forever
snmpEngine.transportDispatcher.jobStarted(1)
# Run I/O dispatcher which would receive queries and send responses
try:
snmpEngine.transportDispatcher.runDispatcher()
except:
snmpEngine.transportDispatcher.closeDispatcher()
raise
Download
script.
Serve non-default MIB tree¶
Listen and respond to SNMP GET/SET/GETNEXT/GETBULK queries with the following options:
- SNMPv3
- with USM username usr-md5-none
- using alternative set of Managed Objects addressed by contextEngineId: 8000000001020304, contextName: my-context
- allow access to SNMPv2-MIB objects (1.3.6.1.2.1)
- over IPv4/UDP, listening at 127.0.0.1:161
Either of the following Net-SNMP commands will walk this Agent:
$ snmpwalk -v3 -u usr-md5-none -l authNoPriv -A authkey1 -E 8000000001020304 -n my-context 127.0.0.1 .1.3.6
$ snmpwalk -v3 -u usr-md5-none -l authNoPriv -A authkey1 -E 8000000001020304 127.0.0.1 .1.3.6
from pysnmp.entity import engine, config
from pysnmp.entity.rfc3413 import cmdrsp, context
from pysnmp.carrier.asyncore.dgram import udp
from pysnmp.smi import instrum, builder
from pysnmp.proto.api import v2c
# Create SNMP engine
snmpEngine = engine.SnmpEngine()
# Transport setup
# UDP over IPv4
config.addTransport(
snmpEngine,
udp.domainName,
udp.UdpTransport().openServerMode(('127.0.0.1', 161))
)
# SNMPv3/USM setup
# user: usr-md5-none, auth: MD5, priv NONE
config.addV3User(
snmpEngine, 'usr-md5-none',
config.usmHMACMD5AuthProtocol, 'authkey1'
)
# Allow full MIB access for each user at VACM
config.addVacmUser(snmpEngine, 3, 'usr-md5-none', 'authNoPriv', (1,3,6,1,2,1), (1,3,6,1,2,1))
# Create an SNMP context with ContextEngineId = 8000000001020304
snmpContext = context.SnmpContext(
snmpEngine, contextEngineId=v2c.OctetString(hexValue='8000000001020304')
)
# Create an [empty] set of Managed Objects (MibBuilder), pass it to
# Management Instrumentation Controller and register at SNMP Context
# under ContextName 'my-context'
snmpContext.registerContextName(
v2c.OctetString('my-context'), # Context Name
instrum.MibInstrumController(builder.MibBuilder()) # Managed Objects
)
# Register SNMP Applications at the SNMP engine for particular SNMP context
cmdrsp.GetCommandResponder(snmpEngine, snmpContext)
cmdrsp.SetCommandResponder(snmpEngine, snmpContext)
cmdrsp.NextCommandResponder(snmpEngine, snmpContext)
cmdrsp.BulkCommandResponder(snmpEngine, snmpContext)
# Register an imaginary never-ending job to keep I/O dispatcher running forever
snmpEngine.transportDispatcher.jobStarted(1)
# Run I/O dispatcher which would receive queries and send responses
try:
snmpEngine.transportDispatcher.runDispatcher()
except:
snmpEngine.transportDispatcher.closeDispatcher()
raise
Download
script.
Custom MIB Controller¶
Listen and respond to SNMP GET/SET/GETNEXT/GETBULK queries with the following options:
- SNMPv3
- with USM username usr-none-none
- using alternative set of Managed Objects addressed by contextName: my-context
- allow access to SNMPv2-MIB objects (1.3.6.1.2.1)
- over IPv4/UDP, listening at 127.0.0.1:161
The following Net-SNMP command will send GET request to this Agent:
$ snmpget -v3 -u usr-none-none -l noAuthNoPriv -n my-context -Ir 127.0.0.1 sysDescr.0
from pysnmp.entity import engine, config
from pysnmp.entity.rfc3413 import cmdrsp, context
from pysnmp.carrier.asyncore.dgram import udp
from pysnmp.smi import instrum
from pysnmp.proto.api import v2c
# Create SNMP engine
snmpEngine = engine.SnmpEngine()
# Transport setup
# UDP over IPv4
config.addTransport(
snmpEngine,
udp.domainName,
udp.UdpTransport().openServerMode(('127.0.0.1', 161))
)
# SNMPv3/USM setup
# user: usr-none-none, auth: NONE, priv NONE
config.addV3User(
snmpEngine, 'usr-none-none'
)
# Allow full MIB access for each user at VACM
config.addVacmUser(snmpEngine, 3, 'usr-none-none', 'noAuthNoPriv', (1,3,6,1,2,1), (1,3,6,1,2,1))
# Create an SNMP context
snmpContext = context.SnmpContext(snmpEngine)
# Very basic Management Instrumentation Controller without
# any Managed Objects attached. It supports only GET's and
# always echos request var-binds in response.
class EchoMibInstrumController(instrum.AbstractMibInstrumController):
def readVars(self, vars, acInfo=(None, None)):
return [ (ov[0], v2c.OctetString('You queried OID %s' % ov[0])) for ov in vars]
# Create a custom Management Instrumentation Controller and register at
# SNMP Context under ContextName 'my-context'
snmpContext.registerContextName(
v2c.OctetString('my-context'), # Context Name
EchoMibInstrumController() # Management Instrumentation
)
# Register GET&SET Applications at the SNMP engine for a custom SNMP context
cmdrsp.GetCommandResponder(snmpEngine, snmpContext)
cmdrsp.SetCommandResponder(snmpEngine, snmpContext)
# Register an imaginary never-ending job to keep I/O dispatcher running forever
snmpEngine.transportDispatcher.jobStarted(1)
# Run I/O dispatcher which would receive queries and send responses
try:
snmpEngine.transportDispatcher.runDispatcher()
except:
snmpEngine.transportDispatcher.closeDispatcher()
raise
Download
script.
See also: library reference.