snimpy.snmp.SNMPNoSuchObject: No such object was found

[edouard-lopez]

I'm having an exception raised, but I don't get why

snimpy.snmp.SNMPNoSuchObject: No such object was found

Code

from snimpy import manager as snimpy

def snmp(hostname, oids, mibs):
    logger.debug(hostname)
    logger.debug(oids)
    logger.debug(mibs)
    for mib in mibs:
        snimpy.load(mib)

    session = snimpy.snmp.Session(hostname, "public", 1)
    details = session.get(*oids)

    return [{
                'oid': '.' + '.'.join(repr(node) for node in oid[0]),
                'value': oid[1]
            } for oid in details]

oids = ['.1.3.6.1.2.1.25.3.2.1.3.1', '.1.3.6.1.2.1.43.10.2.1.4.1.1.1.3.6.1.2.1.1.4.0', '.1.3.6.1.2.1.1.1.0', '.1.3.6.1.2.1.1.5.0', '.1.3.6.1.2.1.1.3.0']
hostname = '192.168.2.250'
mibs = ['DISMAN-EVENT-MIB', 'HOST-RESOURCES-MIB', 'SNMPv2-MIB', 'SNMPv2-SMI']
snmp(hostname, oids, mibs)

Error

>>> scanner.get_device_infos('192.168.2.250')
Traceback (most recent call last):
  File "<input>", line 1, in <module>
  File "~/project/daemon/api/scanner.py", line 62, in get_device_infos
    infos = self.network_tools.snmp(hostname, oids, mibs)
  File "~/project/daemon/api/network_tools.py", line 26, in snmp
    logger.debug(type(oids))
  File "~/project/env/lib/python3.5/site-packages/snimpy/snmp.py", line 286, in get
    return self._op(self._cmdgen.getCmd, *oids)
  File "~/project/env/lib/python3.5/site-packages/snimpy/snmp.py", line 278, in _op
    return tuple([(oid, self._convert(val)) for oid, val in results])
  File "~/project/env/lib/python3.5/site-packages/snimpy/snmp.py", line 278, in <listcomp>
    return tuple([(oid, self._convert(val)) for oid, val in results])
  File "~/project/env/lib/python3.5/site-packages/snimpy/snmp.py", line 249, in _convert
    self._check_exception(value)
  File "~/project/env/lib/python3.5/site-packages/snimpy/snmp.py", line 217, in _check_exception
    raise SNMPNoSuchObject("No such object was found")  # nopep8
snimpy.snmp.SNMPNoSuchObject: No such object was found

Doing it in bash works

Reaching the equipment using bash and snmpget command works fine:

declare -a oids=(
'.1.3.6.1.2.1.25.3.2.1.3.1'  # HOST-RESOURCES-MIB::hrDeviceDescr.1
'.1.3.6.1.2.1.43.10.2.1.4.1.1'  # SNMPv2-SMI::mib-2.43.10.2.1.4.1.1 page count
'.1.3.6.1.2.1.1.4.0'  # SNMPv2-MIB::sysContact.0
'.1.3.6.1.2.1.1.1.0'  # SNMPv2-MIB::sysDescr.0
'.1.3.6.1.2.1.1.5.0'  # SNMPv2-MIB::sysName.0
'.1.3.6.1.2.1.1.3.0'  # DISMAN-EVENT-MIB::sysUpTimeInstance
)

for oid in ${oids[@]}; do
    echo "$oid"
    snmpget -v 1 -t .3 -r 2 -c public 192.168.2.250 -m +SNMPv2-MIB "$oid"
    echo
done

output:

.1.3.6.1.2.1.25.3.2.1.3.1
HOST-RESOURCES-MIB::hrDeviceDescr.1 = STRING: Brother HL-5250DN series

.1.3.6.1.2.1.43.10.2.1.4.1.1
SNMPv2-SMI::mib-2.43.10.2.1.4.1.1 = Counter32: 22629

.1.3.6.1.2.1.1.4.0
SNMPv2-MIB::sysContact.0 = STRING: 

.1.3.6.1.2.1.1.1.0
SNMPv2-MIB::sysDescr.0 = STRING: Brother NC-6400h, Firmware Ver.1.01  (05.08.31),MID 84UZ92

.1.3.6.1.2.1.1.5.0
SNMPv2-MIB::sysName.0 = STRING: BRN_7D3B43

.1.3.6.1.2.1.1.3.0
DISMAN-EVENT-MIB::sysUpTimeInstance = Timeticks: (168019770) 19 days, 10:43:17.70

Question

What's the matter here?

[edouard-lopez]

I check to see if one of the oid was problematic and it '.1.3.6.1.2.1.43.10.2.1.4.1.1' is the culprit

Fails

oids = [
    '.1.3.6.1.2.1.43.10.2.1.4.1.1'  # SNMPv2-SMI::mib-2.43.10.2.1.4.1.1 page count
    '.1.3.6.1.2.1.25.3.2.1.3.1',  # HOST-RESOURCES-MIB::hrDeviceDescr.1
]

Works

oids = [
    '.1.3.6.1.2.1.25.3.2.1.3.1',  # HOST-RESOURCES-MIB::hrDeviceDescr.1
    '.1.3.6.1.2.1.43.10.2.1.4.1.1'  # SNMPv2-SMI::mib-2.43.10.2.1.4.1.1 page count
]

I tried again with the full list and putting the problematic oid as the last item of the list and it work…

oids = [
    '.1.3.6.1.2.1.25.3.2.1.3.1',  # HOST-RESOURCES-MIB::hrDeviceDescr.1
    '.1.3.6.1.2.1.1.4.0',  # SNMPv2-MIB::sysContact.0
    '.1.3.6.1.2.1.1.1.0',  # SNMPv2-MIB::sysDescr.0
    '.1.3.6.1.2.1.1.5.0',  # SNMPv2-MIB::sysName.0
    '.1.3.6.1.2.1.1.3.0',  # DISMAN-EVENT-MIB::sysUpTimeInstance
    '.1.3.6.1.2.1.43.10.2.1.4.1.1'  # SNMPv2-SMI::mib-2.43.10.2.1.4.1.1 page count
]

Why is the oids order relevant to session.get(*oids)? cc @vincentbernat

[vincentbernat]

Error reporting with SNMPv1 is misleading. You could first try with SNMPv2 instead.

Your snmpget is not equivalent. Try this instead:

declare -a oids=(
'.1.3.6.1.2.1.25.3.2.1.3.1'  # HOST-RESOURCES-MIB::hrDeviceDescr.1
'.1.3.6.1.2.1.43.10.2.1.4.1.1'  # SNMPv2-SMI::mib-2.43.10.2.1.4.1.1 page count
'.1.3.6.1.2.1.1.4.0'  # SNMPv2-MIB::sysContact.0
'.1.3.6.1.2.1.1.1.0'  # SNMPv2-MIB::sysDescr.0
'.1.3.6.1.2.1.1.5.0'  # SNMPv2-MIB::sysName.0
'.1.3.6.1.2.1.1.3.0'  # DISMAN-EVENT-MIB::sysUpTimeInstance
)

snmpget -v 1 -t .3 -r 2 -c public 192.168.2.250 -m +SNMPv2-MIB ${oids[@]}

I suspect you'll also get the same kind of error. Order is unimportant but there can be a bug in the agent side (server side).

[edouard-lopez]

Bash is working fine, it's the python code that's not working as expected.