Advanced Command Generator¶

Concurrent queries¶

Send multiple SNMP GET requests at once using the following options:

with SNMPv2c, community ‘public’
over IPv4/UDP
to multiple Agents at localhost
for instance of SNMPv2-MIB::sysDescr.0 MIB object
based on asyncio I/O framework

Functionally similar to:

$ snmpget -v2c -c public localhost:161 SNMPv2-MIB::sysDescr.0
$ snmpget -v2c -c public localhost:162 SNMPv2-MIB::sysDescr.0
$ snmpget -v2c -c public localhost:163 SNMPv2-MIB::sysDescr.0

import asyncio

from pysnmp.hlapi.asyncio import *


async def getone(snmpEngine, hostname):
    errorIndication, errorStatus, errorIndex, varBinds = await get_cmd(
        snmpEngine,
        CommunityData("public"),
        UdpTransportTarget(hostname),
        ContextData(),
        ObjectType(ObjectIdentity("SNMPv2-MIB", "sysDescr", 0)),
    )

    if errorIndication:
        print(f"{hostname}: {errorIndication}")
    elif errorStatus:
        print(
            "{} at {}".format(
                errorStatus.prettyPrint(),
                errorIndex and varBinds[int(errorIndex) - 1][0] or "?",
            )
        )
    else:
        for varBind in varBinds:
            print(" = ".join([x.prettyPrint() for x in varBind]))


snmpEngine = SnmpEngine()


async def main():
    await asyncio.gather(
        getone(snmpEngine, ("localhost", 161)),
        getone(snmpEngine, ("localhost6", 161)),
        getone(snmpEngine, ("localhost", 163)),
    )


asyncio.run(main())

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Sequential queries¶

Send multiple SNMP GET requests one by one using the following options:

with SNMPv2c, community ‘public’
over IPv4/UDP
to multiple Agents at localhost
for instance of SNMPv2-MIB::sysDescr.0 MIB object
based on asyncio I/O framework

Functionally similar to:

$ snmpget -v2c -c public localhost:161 SNMPv2-MIB::sysDescr.0
$ snmpget -v2c -c public localhost:162 SNMPv2-MIB::sysDescr.0
$ snmpget -v2c -c public localhost:163 SNMPv2-MIB::sysDescr.0

import asyncio

from pysnmp.hlapi.asyncio import *


async def getone(snmpEngine, hostname):
    errorIndication, errorStatus, errorIndex, varBinds = await get_cmd(
        snmpEngine,
        CommunityData("public"),
        UdpTransportTarget(hostname),
        ContextData(),
        ObjectType(ObjectIdentity("SNMPv2-MIB", "sysDescr", 0)),
    )

    if errorIndication:
        print(f"{hostname}: {errorIndication}")
    elif errorStatus:
        print(
            "{} at {}".format(
                errorStatus.prettyPrint(),
                errorIndex and varBinds[int(errorIndex) - 1][0] or "?",
            )
        )
    else:
        for varBind in varBinds:
            print(" = ".join([x.prettyPrint() for x in varBind]))


async def getall(snmpEngine, hostnames):
    for hostname in hostnames:
        await getone(snmpEngine, hostname)


snmpEngine = SnmpEngine()

asyncio.run(
    getall(snmpEngine, [("localhost", 161), ("localhost6", 161), ("localhost", 163)])
)

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SNMP over TCP¶

Send SNMP GET request using the following options:

with SNMPv2c, community ‘public’

over IPv4/TCP (RFC 3430)

to an Agent at localhost:161

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

Based on asyncio I/O framework

Functionally similar to:

$ snmpget -v2c -c public tcp:localhost:161 SNMPv2-MIB::sysDescr.0

TCP is worth reaching for when a response would be too large to be sure of over a datagram – a wide GETBULK that would otherwise fragment or come back tooBig – when the path filters UDP or sits behind a stateful NAT, or when the caller needs to tell a device that declined to answer from one it could not reach. Over UDP those look alike: both are silence. Here a refused connection comes back as a transportFailure error indication instead of waiting out the retry schedule.

Both ends have to support it, and the agent has to be listening on TCP. RFC 3430 is a transport mapping only – it implies no security of its own, so use SNMPv3 with authPriv where the traffic needs protecting.

import asyncio

from pysnmp.hlapi.asyncio import *


async def run():
    snmpEngine = SnmpEngine()
    errorIndication, errorStatus, errorIndex, varBinds = await get_cmd(
        snmpEngine,
        CommunityData("public"),
        TcpTransportTarget(("localhost", 161)),
        ContextData(),
        ObjectType(ObjectIdentity("SNMPv2-MIB", "sysDescr", 0)),
    )

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

    snmpEngine.transportDispatcher.closeDispatcher()


asyncio.run(run())

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