# Transport tweaks

## 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.snmplabs.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.snmplabs.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.asyncore.dispatch import AsyncoreDispatcher
    from pysnmp.carrier.asyncore.dgram import udp, udp6, unix
    from pyasn1.codec.ber import encoder
    from pysnmp.proto import api

    # Protocol version to use
    pMod = api.protoModules[api.protoVersion1]
    # pMod = api.protoModules[api.protoVersion2c]

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

    # Traps have quite different semantics across proto versions
    if pMod == api.protoModules[api.protoVersion1]:
        pMod.apiTrapPDU.setEnterprise(trapPDU, (1, 3, 6, 1, 1, 2, 3, 4, 1))
        pMod.apiTrapPDU.setGenericTrap(trapPDU, 'coldStart')

    # Build message
    trapMsg = pMod.Message()
    pMod.apiMessage.setDefaults(trapMsg)
    pMod.apiMessage.setCommunity(trapMsg, 'public')
    pMod.apiMessage.setPDU(trapMsg, trapPDU)

    transportDispatcher = AsyncoreDispatcher()

    # UDP/IPv4
    transportDispatcher.registerTransport(
        udp.domainName, udp.UdpSocketTransport().openClientMode()
    )
    transportDispatcher.sendMessage(
        encoder.encode(trapMsg), udp.domainName, ('demo.snmplabs.com', 162)
    )

    # UDP/IPv6
    transportDispatcher.registerTransport(
        udp6.domainName, udp6.Udp6SocketTransport().openClientMode()
    )
    transportDispatcher.sendMessage(
        encoder.encode(trapMsg), udp6.domainName, ('::1', 162)
    )

    ## Local domain socket
    # transportDispatcher.registerTransport(
    #    unix.domainName, unix.UnixSocketTransport().openClientMode()
    # )
    # transportDispatcher.sendMessage(
    #    encoder.encode(trapMsg), unix.domainName, '/tmp/snmp-manager'
    # )

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

    transportDispatcher.closeDispatcher()

`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.snmplabs.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.snmplabs.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 time import time
    from pysnmp.carrier.asynsock.dispatch import AsynsockDispatcher
    from pysnmp.carrier.asynsock.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.setDefaults(reqPDU)

    # Build message
    trapMsg = pMod.Message()
    pMod.apiMessage.setDefaults(trapMsg)
    pMod.apiMessage.setCommunity(trapMsg, 'public')
    pMod.apiMessage.setPDU(trapMsg, reqPDU)

    startedAt = time()

    def cbTimerFun(timeNow):
        if timeNow - startedAt > 3:
            raise Exception("Request timed out")

    # noinspection PyUnusedLocal,PyUnusedLocal
    def cbRecvFun(transportDispatcher, transportDomain, transportAddress,
                  wholeMsg, reqPDU=reqPDU):
        while wholeMsg:
            rspMsg, wholeMsg = decoder.decode(wholeMsg, asn1Spec=pMod.Message())
            rspPDU = pMod.apiMessage.getPDU(rspMsg)
            # Match response to request
            if pMod.apiPDU.getRequestID(reqPDU) == pMod.apiPDU.getRequestID(rspPDU):
                # Check for SNMP errors reported
                errorStatus = pMod.apiPDU.getErrorStatus(rspPDU)
                if errorStatus:
                    print(errorStatus.prettyPrint())
                else:
                    print('INFORM message delivered, response var-binds follow')
                    for oid, val in pMod.apiPDU.getVarBinds(rspPDU):
                        print('%s = %s' % (oid.prettyPrint(), val.prettyPrint()))
                transportDispatcher.jobFinished(1)
        return wholeMsg

    transportDispatcher = AsynsockDispatcher()

    transportDispatcher.registerRecvCbFun(cbRecvFun)
    transportDispatcher.registerTimerCbFun(cbTimerFun)

    # UDP/IPv4
    transportDispatcher.registerTransport(
        udp.domainName, udp.UdpSocketTransport().openClientMode()
    )
    transportDispatcher.sendMessage(
        encoder.encode(trapMsg), udp.domainName, ('demo.snmplabs.com', 162)
    )
    transportDispatcher.jobStarted(1)

    # UDP/IPv6
    # transportDispatcher.registerTransport(
    #    udp6.domainName, udp6.Udp6SocketTransport().openClientMode()
    # )
    # transportDispatcher.sendMessage(
    #    encoder.encode(trapMsg), udp6.domainName, ('::1', 162)
    # )
    # transportDispatcher.jobStarted(1)

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

    transportDispatcher.closeDispatcher()

`Download` script.

See also: library reference.