# Walking operations

## Bulk walk MIB

Send a series of SNMP GETBULK requests * with SNMPv2c, community ‘public’ * over IPv4/UDP * to an Agent at 104.236.166.95:161 * with values non-repeaters = 0, max-repetitions = 25 * 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:

$ snmpbulkwalk -v2c -c public -C n0 -C r25 -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.entity.rfc3413 import cmdgen
    from pysnmp.carrier.asyncore.dgram import udp

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

    #
    # SNMPv2c 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  # stop on error
        if errorStatus:
            print('%s at %s' % (errorStatus.prettyPrint(),
                                errorIndex and varBindTable[-1][int(errorIndex) - 1][0] or '?'))
            return  # stop on error
        for varBindRow in varBindTable:
            for oid, val in varBindRow:
                print('%s = %s' % (oid.prettyPrint(), val.prettyPrint()))
        return True  # signal dispatcher to continue walking

    # Prepare initial request to be sent
    cmdgen.BulkCommandGenerator().sendVarBinds(
        snmpEngine,
        'my-router',
        None, '',  # contextEngineId, contextName
        0, 25,  # non-repeaters, max-repetitions
        [((1, 3, 6, 1, 2, 1, 1), None),
         ((1, 3, 6, 1, 4, 1, 1), None)],
        cbFun
    )

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

`Download` script.

## Fetch two subtrees in parallel

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

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

    #
    # 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', 0)

    #
    # 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 oid, val in varBindRow:
                print('%s = %s' % (oid.prettyPrint(), val.prettyPrint()))
        return 1  # signal dispatcher to continue

    # Prepare initial request to be sent
    cmdgen.NextCommandGenerator().sendVarBinds(
        snmpEngine,
        'my-router',
        None, '',  # contextEngineId, contextName
        [((1, 3, 6, 1, 2, 1, 1), None),
         ((1, 3, 6, 1, 4, 1, 1), None)],
        cbFun
    )

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

`Download` script.

See also: library reference.