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# Transport Tweaks (Agent Side, v1arch)

## TRAP over multiple transports

The following script sends two SNMP TRAP notification using the following options:

- with SNMPv1

- with community name ‘public’

- over IPv4/UDP and IPv6/UDP

- send TRAP notification

- to a Manager at demo.pysnmp.com:162 and [::1]

- with TRAP ID ‘coldStart’ specified as an OID

- include managed objects information:

- with default Uptime value

- with default Agent Address with ‘127.0.0.1’

- overriding Enterprise OID with 1.3.6.1.4.1.20408.4.1.1.2

The following Net-SNMP commands will produce similar SNMP notification:

$ snmptrap -v1 -c public udp:demo.pysnmp.com 1.3.6.1.4.1.20408.4.1.1.2 127.0.0.1 1 0 12345
$ snmptrap -v1 -c public udp6:[::1] 1.3.6.1.4.1.20408.4.1.1.2 127.0.0.1 1 0 12345

    from pysnmp.carrier.asyncio.dispatch import AsyncioDispatcher
    from pysnmp.carrier.asyncio.dgram import udp, udp6
    from pyasn1.codec.ber import encoder
    from pysnmp.proto import api

    # Protocol version to use
    pMod = api.PROTOCOL_MODULES[api.SNMP_VERSION_1]
    # pMod = api.PROTOCOL_MODULES[api.SNMP_VERSION_2C]

    # Build PDU
    trapPDU = pMod.TrapPDU()
    pMod.apiTrapPDU.set_defaults(trapPDU)

    # Traps have quite different semantics across proto versions
    if pMod == api.PROTOCOL_MODULES[api.SNMP_VERSION_1]:
        pMod.apiTrapPDU.set_enterprise(trapPDU, (1, 3, 6, 1, 1, 2, 3, 4, 1))
        pMod.apiTrapPDU.set_generic_trap(trapPDU, "coldStart")

    # Build message
    trapMsg = pMod.Message()
    pMod.apiMessage.set_defaults(trapMsg)
    pMod.apiMessage.set_community(trapMsg, "public")
    pMod.apiMessage.set_pdu(trapMsg, trapPDU)

    transportDispatcher = AsyncioDispatcher()

    # UDP/IPv4
    transportDispatcher.register_transport(
        udp.DOMAIN_NAME, udp.UdpAsyncioTransport().open_client_mode()
    )
    transportDispatcher.send_message(
        encoder.encode(trapMsg), udp.DOMAIN_NAME, ("demo.pysnmp.com", 162)
    )

    # UDP/IPv6
    transportDispatcher.register_transport(
        udp6.DOMAIN_NAME, udp6.Udp6AsyncioTransport().open_client_mode()
    )
    transportDispatcher.send_message(
        encoder.encode(trapMsg), udp6.DOMAIN_NAME, ("::1", 162)
    )

    # Dispatcher will finish as all scheduled messages are sent
    transportDispatcher.run_dispatcher(3)

    transportDispatcher.close_dispatcher()

`Download` script.

## INFORM over multiple transports

The following script sends SNMP INFORM notification using the following options:

- with SNMPv2c

- with community name ‘public’

- over IPv4/UDP and IPv6/UDP

- send INFORM notification

- to a Manager at demo.pysnmp.com:162 and [::1]:162

- with TRAP ID ‘coldStart’ specified as an OID

The following Net-SNMP command will produce similar SNMP notification:

$ snmpinform -v2c -c public udp:demo.pysnmp.com 0 1.3.6.1.6.3.1.1.5.1
$ snmpinform -v2c -c public udp6:[::1] 0 1.3.6.1.6.3.1.1.5.1

    from pysnmp.carrier.asyncio.dispatch import AsyncioDispatcher
    from pysnmp.carrier.asyncio.dgram import udp, udp6
    from pyasn1.codec.ber import encoder, decoder
    from pysnmp.proto.api import v2c as pMod

    # Build PDU
    reqPDU = pMod.InformRequestPDU()
    pMod.apiTrapPDU.set_defaults(reqPDU)

    # Build message
    trapMsg = pMod.Message()
    pMod.apiMessage.set_defaults(trapMsg)
    pMod.apiMessage.set_community(trapMsg, "public")
    pMod.apiMessage.set_pdu(trapMsg, reqPDU)

    # noinspection PyUnusedLocal,PyUnusedLocal
    def cbRecvFun(
        transportDispatcher, transportDomain, transportAddress, wholeMsg, reqPDU=reqPDU
    ):
        while wholeMsg:
            rspMsg, wholeMsg = decoder.decode(wholeMsg, asn1Spec=pMod.Message())
            rspPDU = pMod.apiMessage.get_pdu(rspMsg)
            # Match response to request
            if pMod.apiPDU.get_request_id(reqPDU) == pMod.apiPDU.get_request_id(rspPDU):
                # Check for SNMP errors reported
                errorStatus = pMod.apiPDU.get_error_status(rspPDU)
                if errorStatus:
                    print(errorStatus.prettyPrint())
                else:
                    print("INFORM message delivered, response var-binds follow")
                    for oid, val in pMod.apiPDU.get_varbinds(rspPDU):
                        print(f"{oid.prettyPrint()} = {val.prettyPrint()}")
                transportDispatcher.job_finished(1)
        return wholeMsg

    transportDispatcher = AsyncioDispatcher()

    transportDispatcher.register_recv_callback(cbRecvFun)

    # UDP/IPv4
    transportDispatcher.register_transport(
        udp.DOMAIN_NAME, udp.UdpAsyncioTransport().open_client_mode()
    )
    transportDispatcher.send_message(
        encoder.encode(trapMsg), udp.DOMAIN_NAME, ("demo.pysnmp.com", 162)
    )
    transportDispatcher.jobStarted(1)

    # UDP/IPv6
    # transportDispatcher.register_transport(
    #    udp6.domainName, udp6.Udp6AsyncioTransport().open_client_mode()
    # )
    # transportDispatcher.send_message(
    #    encoder.encode(trapMsg), udp6.domainName, ('::1', 162)
    # )
    # transportDispatcher.job_started(1)

    # Dispatcher will finish as all scheduled messages are sent
    transportDispatcher.run_dispatcher(3)

    transportDispatcher.close_dispatcher()

`Download` script.

See also: library reference.