[pysnmp-users] Help understanding walking MIB

[Denis F. <pyt...@le...>]

Hi,

I am using pysnmp 4.3.0 with Linux/Debian 8. I have the following code
(basically getbulk-limit-number-of-packets.py example) :

------8<------
from pysnmp.hlapi import *

for errorIndication, \
    errorStatus, errorIndex, \
    varBinds in bulkCmd(SnmpEngine(),
                        CommunityData('public'),
                        UdpTransportTarget(('snmp', 161)),
                        ContextData(),
                        0, 50,
                        ObjectType(ObjectIdentity('1.3.6.1.2.1.2.2.1')),
                        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 ]))
------8<------

I'm expecting it to return only what lies under 1.3.6.1.2.1.2.2.1 but I get :

------8<------
[...]
SNMPv2-SMI::mib-2."2.2.1.22.3" = 0.0
SNMPv2-SMI::mib-2."2.2.1.22.4" = 0.0
SNMPv2-SMI::mib-2."2.2.1.22.5" = 0.0
SNMPv2-SMI::mib-2."2.2.1.22.6" = 0.0
SNMPv2-SMI::mib-2."2.2.1.22.7" = 0.0
SNMPv2-SMI::mib-2."2.2.1.22.8" = 0.0
SNMPv2-SMI::mib-2."2.2.1.22.9" = 0.0
SNMPv2-SMI::mib-2."4.1.0" = 1
SNMPv2-SMI::mib-2."4.2.0" = 64
SNMPv2-SMI::mib-2."4.3.0" = 8165257
SNMPv2-SMI::mib-2."4.4.0" = 0
SNMPv2-SMI::mib-2."4.5.0" = 1176834
SNMPv2-SMI::mib-2."4.6.0" = 6851141
SNMPv2-SMI::mib-2."4.7.0" = 39
[...]
------8<------

Why is it returning results from 1.3.6.1.2.1.4 ?
Using net-snmp snmpwalk returns only the MIB I asked for.

On a similar side, if I have two MIBs to be walked, like in the following code
:
------8<------
from pysnmp.hlapi import *

for errorIndication, \
    errorStatus, errorIndex, \
    varBinds in bulkCmd(SnmpEngine(),
                        CommunityData('public'),
                        UdpTransportTarget(('snmp', 161)),
                        ContextData(),
                        0, 50,
                        ObjectType(ObjectIdentity('1.3.6.1.2.1.2.2.1')),
                        ObjectType(ObjectIdentity('1.3.6.1.2.1.31.1.1.1')),
                        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 ]))

------8<------

I get :

------8<------
SNMPv2-SMI::mib-2."2.2.1.1.1" = 1
SNMPv2-SMI::mib-2."31.1.1.1.1.1" = em0
SNMPv2-SMI::mib-2."31.1.1.1.1.2" = em1
SNMPv2-SMI::mib-2."31.1.1.1.1.3" = em2
[...]
SNMPv2-SMI::mib-2."31.1.6.0" = 1406953
SNMPv2-SMI::enterprises."2021.13.15.1.1.1.1" = 1
SNMPv2-SMI::enterprises."2021.13.15.1.1.2.1" = sd0
SNMPv2-SMI::enterprises."2021.13.15.1.1.3.1" = 1938226688
------8<------

Only the first OID of the first MIB, what looks like the full second MIB and
part of a third one... I was expecting the full first and second MIBs.

What do I get wrong about this behaviour ?

Thank you in advance,
Denis