MIB tweaks
**********


Walk Agent and resolve variables at MIB
=======================================

Send a series of SNMP GETNEXT requests with the following options:

* with SNMPv1, community 'public'

* over IPv4/UDP

* to an Agent at 104.236.166.95:161

* for two OIDs in tuple form

* stop on end-of-mib condition for both OIDs

This script performs similar to the following Net-SNMP command:

   $ snmpwalk -v1 -c public -ObentU 104.236.166.95 1.3.6.1.2.1.1 1.3.6.1.4.1.1

   from pysnmp.entity import engine, config
   from pysnmp.carrier.asyncore.dgram import udp
   from pysnmp.entity.rfc3413 import cmdgen
   from pysnmp.smi import compiler, view, rfc1902

   # Create SNMP engine instance
   snmpEngine = engine.SnmpEngine()

   # Attach MIB compiler to SNMP Engine (MIB Builder)
   # This call will fail if PySMI is not present on the system
   compiler.addMibCompiler(snmpEngine.getMibBuilder())
   # ... alternatively, this call will not complain on missing PySMI
   # compiler.addMibCompiler(snmpEngine.getMibBuilder(), ifAvailable=True)

   # Used for MIB objects resolution
   mibViewController = view.MibViewController(snmpEngine.getMibBuilder())

   # 
   #
   # SNMPv1/2c setup
   #

   # SecurityName <-> CommunityName mapping
   config.addV1System(snmpEngine, 'my-area', 'public')

   # Specify security settings per SecurityName (SNMPv1 - 0, SNMPv2c - 1)
   config.addTargetParams(snmpEngine, 'my-creds', 'my-area', 'noAuthNoPriv', 1)

   #
   # Setup transport endpoint and bind it with security settings yielding
   # a target name
   #

   # UDP/IPv4
   config.addTransport(
       snmpEngine,
       udp.domainName,
       udp.UdpSocketTransport().openClientMode()
   )
   config.addTargetAddr(
       snmpEngine, 'my-router',
       udp.domainName, ('104.236.166.95', 161),
       'my-creds'
   )


   # Error/response receiver
   # noinspection PyUnusedLocal,PyUnusedLocal,PyUnusedLocal
   def cbFun(snmpEngine, sendRequestHandle, errorIndication,
             errorStatus, errorIndex, varBindTable, cbCtx):
       if errorIndication:
           print(errorIndication)
           return
       # SNMPv1 response may contain noSuchName error *and* SNMPv2c exception,
       # so we ignore noSuchName error here
       if errorStatus and errorStatus != 2:
           print('%s at %s' % (errorStatus.prettyPrint(),
                               errorIndex and varBindTable[-1][int(errorIndex) - 1][0] or '?'))
           return  # stop on error
       for varBindRow in varBindTable:
           for varBind in varBindRow:
               print(rfc1902.ObjectType(rfc1902.ObjectIdentity(varBind[0]),
                                        varBind[1]).resolveWithMib(mibViewController).prettyPrint())
       return 1  # signal dispatcher to continue


   # Prepare initial request to be sent
   cmdgen.NextCommandGenerator().sendVarBinds(
       snmpEngine,
       'my-router',
       None, '',  # contextEngineId, contextName
       [rfc1902.ObjectType(rfc1902.ObjectIdentity('iso.org.dod')).resolveWithMib(mibViewController),
        rfc1902.ObjectType(rfc1902.ObjectIdentity('IF-MIB', 'ifMIB')).resolveWithMib(mibViewController)],
       cbFun
   )

   # Run I/O dispatcher which would send pending queries and process responses
   snmpEngine.transportDispatcher.runDispatcher()

"Download" script.

See also: library reference.
