# Advanced Command Generator

## Walk Agent, limit number of packets

Send a series of SNMP GETBULK requests using the following options:

- with SNMPv3, user ‘usr-none-none’, no authentication, no privacy

- over IPv4/UDP

- to an Agent at demo.snmplabs.com:161

- for all OIDs past SNMPv2-MIB::system

- run till end-of-mib condition is reported by Agent OR maxCalls == 10 request-response interactions occur

Functionally similar to:

$ snmpbulkwalk -v3 -lnoAuthNoPriv -u usr-none-none -Cn0 -Cr50 demo.snmplabs.com SNMPv2-MIB::system

    from pysnmp.hlapi import *

    for (errorIndication,
         errorStatus,
         errorIndex,
         varBinds) in bulkCmd(SnmpEngine(),
                              UsmUserData('usr-none-none'),
                              UdpTransportTarget(('demo.snmplabs.com', 161)),
                              ContextData(),
                              0, 50,
                              ObjectType(ObjectIdentity('SNMPv2-MIB', 'system')),
                              maxCalls=10):

        if errorIndication:
            print(errorIndication)
            break
        elif errorStatus:
            print('%s at %s' % (errorStatus.prettyPrint(),
                                errorIndex and varBinds[int(errorIndex) - 1][0] or '?'))
            break
        else:
            for varBind in varBinds:
                print(' = '.join([x.prettyPrint() for x in varBind]))

`Download` script.

## Sequence Of GET’s

Send two SNMP GET requests in a row using the following options:

- with SNMPv3, user ‘usr-md5-none’, MD5 authentication, no privacy

- over IPv4/UDP

- to an Agent at demo.snmplabs.com:161

- for IF-MIB::ifInOctets.1 and IF-MIB::ifOutOctets.1 MIB objects

Use a queue of MIB objects to query.

The next() call is used to forward Python iterator to the position where it could consume input

Functionally similar to:

$ snmpget -v3 -l authNoPriv -u usr-md5-none -A authkey1 demo.snmplabs.com IF-MIB::ifInOctets.1

    from pysnmp.hlapi import *

    queue = [[ObjectType(ObjectIdentity('IF-MIB', 'ifInOctets', 1))],
             [ObjectType(ObjectIdentity('IF-MIB', 'ifOutOctets', 1))]]

    iter = getCmd(SnmpEngine(),
                  UsmUserData('usr-md5-none', 'authkey1'),
                  UdpTransportTarget(('demo.snmplabs.com', 161)),
                  ContextData())

    next(iter)

    while queue:
        errorIndication, errorStatus, errorIndex, varBinds = iter.send(queue.pop())
        if errorIndication:
            print(errorIndication)
        elif errorStatus:
            print('%s at %s' % (errorStatus.prettyPrint(),
                                errorIndex and varBinds[int(errorIndex) - 1][0] or '?'))
        else:
            for varBind in varBinds:
                print(' = '.join([x.prettyPrint() for x in varBind]))

`Download` script.

## Custom ContextEngineId

Send SNMP GET request using the following options:

- with SNMPv3 with user ‘usr-md5-des’, MD5 auth and DES privacy protocols

- use remote SNMP Engine ID 0x80004fb805636c6f75644dab22cc (USM autodiscovery will run)

- over IPv4/UDP

- to an Agent at demo.snmplabs.com:161

- setting SNMPv2-MIB::sysName.0 to new value (type coerced from MIB)

Functionally similar to:

$ snmpset -v3 -u usr-md5-des -l authPriv -A authkey1 -X privkey1 -E 80004fb805636c6f75644dab22cc demo.snmplabs.com SNMPv2-MIB::sysORDescr.1 = “new system name”

    from pysnmp.hlapi import *

    errorIndication, errorStatus, errorIndex, varBinds = next(
        setCmd(SnmpEngine(),
               UsmUserData('usr-md5-des', 'authkey1', 'privkey1',
                           securityEngineId=OctetString(hexValue='80004fb805636c6f75644dab22cc')),
               UdpTransportTarget(('demo.snmplabs.com', 161)),
               ContextData(),
               ObjectType(ObjectIdentity('SNMPv2-MIB', 'sysName', 0), 'new system name'))
    )

    if errorIndication:
        print(errorIndication)
    elif errorStatus:
        print('%s at %s' % (errorStatus.prettyPrint(),
                            errorIndex and varBinds[int(errorIndex) - 1][0] or '?'))
    else:
        for varBind in varBinds:
            print(' = '.join([x.prettyPrint() for x in varBind]))

`Download` script.

## Custom ContextEngineId and ContextName

Send SNMP SET request using the following options:

- with SNMPv3 with user ‘usr-md5-none’, MD5 auth and no privacy protocols

- over IPv4/UDP

- to an Agent at demo.snmplabs.com:161

- addressing particular set of Managed Objects at remote SNMP Engine by: * contextEngineId 0x80004fb805636c6f75644dab22cc and * contextName ‘a172334d7d97871b72241397f713fa12’

- setting SNMPv2-MIB::sysName.0 to new value (type taken from MIB)

Functionally similar to:

$ snmpset -v3 -u usr-md5-des -l authPriv -A authkey1 -X privkey1 -E 80004fb805636c6f75644dab22cc -n a172334d7d97871b72241397f713fa12 demo.snmplabs.com SNMPv2-MIB::sysORDescr.1 = “new system name”

    from pysnmp.hlapi import *

    errorIndication, errorStatus, errorIndex, varBinds = next(
        setCmd(SnmpEngine(),
               UsmUserData('usr-md5-none', 'authkey1'),
               UdpTransportTarget(('demo.snmplabs.com', 161)),
               ContextData(contextEngineId=OctetString(hexValue='80004fb805636c6f75644dab22cc'),
                           contextName='da761cfc8c94d3aceef4f60f049105ba'),
               ObjectType(ObjectIdentity('SNMPv2-MIB', 'sysORDescr', 1), 'new system name'))
    )

    if errorIndication:
        print(errorIndication)
    elif errorStatus:
        print('%s at %s' % (errorStatus.prettyPrint(),
                            errorIndex and varBinds[int(errorIndex) - 1][0] or '?'))
    else:
        for varBind in varBinds:
            print(' = '.join([x.prettyPrint() for x in varBind]))

`Download` script.

## Custom SecurityName

Send SNMP GET request using the following options:

- with SNMPv3, user ‘usr-md5-none’, securityName ‘myuser’ MD5 authentication, no privacy

- over IPv4/UDP

- to an Agent at demo.snmplabs.com:161

- for an OID in text form

The securityName parameter can be thought as an alias to userName and allows you to address a USM Table row just as userName does. However securityName can be made human-readable, also it is not an index in usmUserTable, thus duplicate securityName parameters are possible.

    from pysnmp.hlapi import *

    errorIndication, errorStatus, errorIndex, varBinds = next(
        getCmd(SnmpEngine(),
               UsmUserData('usr-md5-none', 'authkey1', securityName='myuser'),
               UdpTransportTarget(('demo.snmplabs.com', 161)),
               ContextData(),
               ObjectType(ObjectIdentity('1.3.6.1.2.1.1.1.0')))
    )

    if errorIndication:
        print(errorIndication)
    elif errorStatus:
        print('%s at %s' % (errorStatus.prettyPrint(),
                            errorIndex and varBinds[int(errorIndex) - 1][0] or '?'))
    else:
        for varBind in varBinds:
            print(' = '.join([x.prettyPrint() for x in varBind]))

`Download` script.

## Discover SNMPv3 SecurityEngineId

Send SNMP GET request using the following scenario and options:

- try to communicate with a SNMPv3 Engine using:

- a non-existing user

- over IPv4/UDP

- to an Agent at demo.snmplabs.com:161

- if remote SNMP Engine ID is discovered, send SNMP GET request:

- with SNMPv3, user ‘usr-md5-none’, MD5 authentication, no privacy

    at discovered securityEngineId

- to the same SNMP Engine ID

- for an OID in text form

    from pysnmp.hlapi import *

    snmpEngine = SnmpEngine()

    transportTarget = UdpTransportTarget(('demo.snmplabs.com', 161))

    #
    # To discover remote SNMP EngineID we will tap on SNMP engine inner workings
    # by setting up execution point observer setup on INTERNAL class PDU processing
    #

    observerContext = {}

    # Register a callback to be invoked at specified execution point of
    # SNMP Engine and passed local variables at execution point's local scope
    snmpEngine.observer.registerObserver(
        lambda e, p, v, c: c.update(securityEngineId=v['securityEngineId']),
        'rfc3412.prepareDataElements:internal',
        cbCtx=observerContext
    )

    # Send probe SNMP request with invalid credentials

    authData = UsmUserData('non-existing-user')

    errorIndication, errorStatus, errorIndex, varBinds = next(
        getCmd(snmpEngine, authData, transportTarget, ContextData(),
               ObjectType(ObjectIdentity('SNMPv2-MIB', 'sysDescr', 0)))
    )

    # See if our SNMP engine received REPORT PDU containing securityEngineId

    if 'securityEngineId' not in observerContext:
        print("Can't discover peer EngineID, errorIndication: %s" % errorIndication)
        raise Exception()

    securityEngineId = observerContext.pop('securityEngineId')

    print('Remote securityEngineId = %s' % securityEngineId.prettyPrint())

    #
    # Query remote SNMP Engine using usmUserTable entry configured for it
    #

    authData = UsmUserData('usr-md5-none', 'authkey1',
                           securityEngineId=securityEngineId)

    errorIndication, errorStatus, errorIndex, varBinds = next(
        getCmd(snmpEngine,
               authData,
               transportTarget,
               ContextData(),
               ObjectType(ObjectIdentity('1.3.6.1.2.1.1.1.0')))
    )

    if errorIndication:
        print(errorIndication)
    elif errorStatus:
        print('%s at %s' % (errorStatus.prettyPrint(),
                            errorIndex and varBinds[int(errorIndex) - 1][0] or '?'))
    else:
        for name, val in varBinds:
            print('%s = %s' % (name.prettyPrint(), val.prettyPrint()))

`Download` script.

## SNMPv3: master auth and privacy keys

Send SNMP GET request using the following options:

- with SNMPv3, user ‘usr-md5-des’, MD5 authentication, DES encryption

- use master auth and privacy keys instead of pass-phrase

- over IPv4/UDP

- to an Agent at demo.snmplabs.com:161

- for SNMPv2-MIB::sysDescr.0 MIB object instance

Functionally similar to:

$ snmpget -v3 -l authPriv -u usr-md5-des -3m 0x1dcf59e86553b3afa5d32fd5d61bf0cf -3M 0xec5ab55e93e1d85cb6846d0f23e845e0 demo.snmplabs.com SNMPv2-MIB::sysDescr.0

    from pysnmp.hlapi import *

    errorIndication, errorStatus, errorIndex, varBinds = next(
        getCmd(SnmpEngine(),
               UsmUserData('usr-md5-des',
                           authKey=OctetString(
                               hexValue='1dcf59e86553b3afa5d32fd5d61bf0cf'),
                           privKey=OctetString(
                               hexValue='ec5ab55e93e1d85cb6846d0f23e845e0'),
                           authKeyType=usmKeyTypeMaster,
                           privKeyType=usmKeyTypeMaster),
               UdpTransportTarget(('demo.snmplabs.com', 161)),
               ContextData(),
               ObjectType(ObjectIdentity('SNMPv2-MIB', 'sysDescr', 0)))
    )

    if errorIndication:
        print(errorIndication)
    elif errorStatus:
        print('%s at %s' % (errorStatus.prettyPrint(),
                            errorIndex and varBinds[int(errorIndex) - 1][0] or '?'))
    else:
        for varBind in varBinds:
            print(' = '.join([x.prettyPrint() for x in varBind]))

`Download` script.

## SNMPv3: localized auth and privacy keys

Send SNMP GET request using the following options:

- with SNMPv3, user ‘usr-md5-des’, MD5 authentication, DES encryption

- use localized auth and privacy keys instead of pass-phrase or master keys

- configure authoritative SNMP engine ID (0x0000000000 can be used as well)

- over IPv4/UDP

- to an Agent at demo.snmplabs.com:161

- for SNMPv2-MIB::sysDescr.0 MIB object instance

Functionally similar to:

$ snmpget -v3 -l authPriv -u usr-md5-des -e 0x80004fb805636c6f75644dab22cc -3k 0x6b99c475259ef7976cf8d028a3381eeb -3K 0x92b5ef98f0a216885e73944e58c07345 demo.snmplabs.com SNMPv2-MIB::sysDescr.0

    from pysnmp.hlapi import *

    errorIndication, errorStatus, errorIndex, varBinds = next(
        getCmd(SnmpEngine(),
               UsmUserData('usr-md5-des',
                           authKey=OctetString(
                               hexValue='6b99c475259ef7976cf8d028a3381eeb'),
                           privKey=OctetString(
                               hexValue='92b5ef98f0a216885e73944e58c07345'),
                           authKeyType=usmKeyTypeLocalized,
                           privKeyType=usmKeyTypeLocalized,
                           securityEngineId=OctetString(
                               hexValue='80004fb805636c6f75644dab22cc')),
               UdpTransportTarget(('demo.snmplabs.com', 161)),
               ContextData(),
               ObjectType(ObjectIdentity('SNMPv2-MIB', 'sysDescr', 0)))
    )

    if errorIndication:
        print(errorIndication)
    elif errorStatus:
        print('%s at %s' % (errorStatus.prettyPrint(),
                            errorIndex and varBinds[int(errorIndex) - 1][0] or '?'))
    else:
        for varBind in varBinds:
            print(' = '.join([x.prettyPrint() for x in varBind]))

`Download` script.

## Query Agents from multiple threads

Send a bunch of SNMP GET requests simultaneously using the following options:

- process 5 GET requests in 3 parallel threads

- with SNMPv1, community ‘public’ and with SNMPv2c, community ‘public’ and with SNMPv3, user ‘usr-md5-des’, MD5 auth and DES privacy

- over IPv4/UDP and over IPv6/UDP

- to an Agent at demo.snmplabs.com:161 and to an Agent at [::1]:161

- for instances of SNMPv2-MIB::sysDescr.0 and SNMPv2-MIB::sysLocation.0 MIB objects

    from sys import version_info
    from threading import Thread
    from pysnmp.hlapi import *

    if version_info[0] == 2:
        from Queue import Queue
    else:
        from queue import Queue

    # List of targets in the following format:
    # ( ( authData, transportTarget, varNames ), ... )
    targets = (
        # 1-st target (SNMPv1 over IPv4/UDP)
        (CommunityData('public', mpModel=0),
         UdpTransportTarget(('demo.snmplabs.com', 161)),
         (ObjectType(ObjectIdentity('SNMPv2-MIB', 'sysDescr', 0)),
          ObjectType(ObjectIdentity('SNMPv2-MIB', 'sysLocation', 0)))),
        # 2-nd target (SNMPv2c over IPv4/UDP)
        (CommunityData('public'),
         UdpTransportTarget(('demo.snmplabs.com', 161)),
         (ObjectType(ObjectIdentity('SNMPv2-MIB', 'sysDescr', 0)),
          ObjectType(ObjectIdentity('SNMPv2-MIB', 'sysLocation', 0)))),
        # 3-nd target (SNMPv2c over IPv4/UDP) - same community and
        # different transport address.
        (CommunityData('public'),
         UdpTransportTarget(('localhost', 161)),
         (ObjectType(ObjectIdentity('SNMPv2-MIB', 'sysContact', 0)),
          ObjectType(ObjectIdentity('SNMPv2-MIB', 'sysName', 0)))),
        # 4-nd target (SNMPv3 over IPv4/UDP)
        (UsmUserData('usr-md5-des', 'authkey1', 'privkey1'),
         UdpTransportTarget(('demo.snmplabs.com', 161)),
         (ObjectType(ObjectIdentity('SNMPv2-MIB', 'sysDescr', 0)),
          ObjectType(ObjectIdentity('SNMPv2-MIB', 'sysLocation', 0)))),
        # 5-th target (SNMPv3 over IPv6/UDP)
        (UsmUserData('usr-md5-none', 'authkey1'),
         Udp6TransportTarget(('::1', 161)),
         (ObjectType(ObjectIdentity('SNMPv2-MIB', 'sysDescr', 0)),
          ObjectType(ObjectIdentity('SNMPv2-MIB', 'sysLocation', 0)))),
        # N-th target
        # ...
    )

    class Worker(Thread):
        def __init__(self, requests, responses):
            Thread.__init__(self)
            self.snmpEngine = SnmpEngine()
            self.requests = requests
            self.responses = responses
            self.setDaemon(True)
            self.start()

        def run(self):
            while True:
                authData, transportTarget, varBinds = self.requests.get()
                self.responses.append(
                    next(getCmd(self.snmpEngine,
                         authData, transportTarget, ContextData(), *varBinds))
                )
                if hasattr(self.requests, 'task_done'):  # 2.5+
                    self.requests.task_done()

    class ThreadPool(object):
        def __init__(self, num_threads):
            self.requests = Queue(num_threads)
            self.responses = []
            for _ in range(num_threads):
                Worker(self.requests, self.responses)

        def addRequest(self, authData, transportTarget, varBinds):
            self.requests.put((authData, transportTarget, varBinds))

        def getResponses(self):
            return self.responses

        def waitCompletion(self):
            if hasattr(self.requests, 'join'):
                self.requests.join()  # 2.5+
            else:
                from time import sleep
                # this is a lame substitute for missing .join()
                # adding an explicit synchronization might be a better solution
                while not self.requests.empty():
                    sleep(1)

    pool = ThreadPool(3)

    # Submit GET requests
    for authData, transportTarget, varBinds in targets:
        pool.addRequest(authData, transportTarget, varBinds)

    # Wait for responses or errors
    pool.waitCompletion()

    # Walk through responses
    for errorIndication, errorStatus, errorIndex, varBinds in pool.getResponses():
        if errorIndication:
            print(errorIndication)
        elif errorStatus:
            print('%s at %s' % (errorStatus.prettyPrint(),
                                errorIndex and varBinds[int(errorIndex) - 1][0] or '?'))
        else:
            for varBind in varBinds:
                print(' = '.join([x.prettyPrint() for x in varBind]))

`Download` script.

See also: library reference.