# Various SNMP versions

## Serving multiple network interfaces

Receive SNMP TRAP/INFORM messages with the following options:

- SNMPv1/SNMPv2c

- with SNMP community “public”

- over IPv4/UDP, listening at 127.0.0.1:162 over IPv4/UDP, listening at 127.0.0.1:2162

- print received data on stdout

Either of the following Net-SNMP commands will send notifications to this receiver:

$ snmptrap -v2c -c public 127.0.0.1:162 123 1.3.6.1.6.3.1.1.5.1 1.3.6.1.2.1.1.5.0 s test
$ snmpinform -v2c -c public 127.0.0.1:2162 123 1.3.6.1.6.3.1.1.5.1

    from pysnmp.entity import engine, config
    from pysnmp.carrier.asyncore.dgram import udp
    from pysnmp.entity.rfc3413 import ntfrcv

    # Create SNMP engine with autogenernated engineID and pre-bound
    # to socket transport dispatcher
    snmpEngine = engine.SnmpEngine()

    # Transport setup

    # UDP over IPv4, first listening interface/port
    config.addTransport(
        snmpEngine,
        udp.domainName + (1,),
        udp.UdpTransport().openServerMode(('127.0.0.1', 162))
    )

    # UDP over IPv4, second listening interface/port
    config.addTransport(
        snmpEngine,
        udp.domainName + (2,),
        udp.UdpTransport().openServerMode(('127.0.0.1', 2162))
    )

    # SNMPv1/2c setup

    # SecurityName <-> CommunityName mapping
    config.addV1System(snmpEngine, 'my-area', 'public')

    # Callback function for receiving notifications
    # noinspection PyUnusedLocal,PyUnusedLocal,PyUnusedLocal
    def cbFun(snmpEngine, stateReference, contextEngineId, contextName,
              varBinds, cbCtx):
        print('Notification from ContextEngineId "%s", ContextName "%s"' % (contextEngineId.prettyPrint(),
                                                                            contextName.prettyPrint()))
        for name, val in varBinds:
            print('%s = %s' % (name.prettyPrint(), val.prettyPrint()))

    # Register SNMP Application at the SNMP engine
    ntfrcv.NotificationReceiver(snmpEngine, cbFun)

    snmpEngine.transportDispatcher.jobStarted(1)  # this job would never finish

    # Run I/O dispatcher which would receive queries and send confirmations
    try:
        snmpEngine.transportDispatcher.runDispatcher()
    except:
        snmpEngine.transportDispatcher.closeDispatcher()
        raise

`Download` script.

## Multiple SNMP USM users

Receive SNMP TRAP/INFORM messages with the following options:

- SNMPv3

- with USM users:

  - ‘usr-md5-des’, auth: MD5, priv DES, ContextEngineId: 8000000001020304

  - ‘usr-md5-none’, auth: MD5, priv NONE, ContextEngineId: 8000000001020304

  - ‘usr-sha-aes128’, auth: SHA, priv AES, ContextEngineId: 8000000001020304

- over IPv4/UDP, listening at 127.0.0.1:162

- print received data on stdout

Either of the following Net-SNMP commands will send notifications to this receiver:

$ snmptrap -v3 -u usr-md5-des -l authPriv -A authkey1 -X privkey1 -e 8000000001020304 127.0.0.1 123 1.3.6.1.6.3.1.1.5.1
$ snmptrap -v3 -u usr-md5-none -l authNoPriv -A authkey1 -e 8000000001020304 127.0.0.1 123 1.3.6.1.6.3.1.1.5.1
$ snmpinform -v3 -u usr-sha-aes128 -l authPriv -a SHA -A authkey1 -x AES -X privkey1 127.0.0.1 123 1.3.6.1.6.3.1.1.5.1

    from pysnmp.entity import engine, config
    from pysnmp.carrier.asyncore.dgram import udp
    from pysnmp.entity.rfc3413 import ntfrcv
    from pysnmp.proto.api import v2c

    # Create SNMP engine with autogenernated engineID and pre-bound
    # to socket transport dispatcher
    snmpEngine = engine.SnmpEngine()

    # Transport setup

    # UDP over IPv4
    config.addTransport(
        snmpEngine,
        udp.domainName,
        udp.UdpTransport().openServerMode(('127.0.0.1', 162))
    )

    # SNMPv3/USM setup

    # user: usr-md5-des, auth: MD5, priv DES
    config.addV3User(
        snmpEngine, 'usr-md5-des',
        config.usmHMACMD5AuthProtocol, 'authkey1',
        config.usmDESPrivProtocol, 'privkey1'
    )

    # user: usr-md5-des, auth: MD5, priv DES, securityEngineId: 8000000001020304
    # this USM entry is used for TRAP receiving purposes
    config.addV3User(
        snmpEngine, 'usr-md5-des',
        config.usmHMACMD5AuthProtocol, 'authkey1',
        config.usmDESPrivProtocol, 'privkey1',
        securityEngineId=v2c.OctetString(hexValue='8000000001020304')
    )

    # user: usr-md5-none, auth: MD5, priv NONE
    config.addV3User(
        snmpEngine, 'usr-md5-none',
        config.usmHMACMD5AuthProtocol, 'authkey1'
    )

    # user: usr-md5-none, auth: MD5, priv NONE, securityEngineId: 8000000001020304
    # this USM entry is used for TRAP receiving purposes
    config.addV3User(
        snmpEngine, 'usr-md5-none',
        config.usmHMACMD5AuthProtocol, 'authkey1',
        securityEngineId=v2c.OctetString(hexValue='8000000001020304')
    )

    # user: usr-sha-aes128, auth: SHA, priv AES
    config.addV3User(
        snmpEngine, 'usr-sha-aes128',
        config.usmHMACSHAAuthProtocol, 'authkey1',
        config.usmAesCfb128Protocol, 'privkey1'
    )
    # user: usr-sha-aes128, auth: SHA, priv AES, securityEngineId: 8000000001020304
    # this USM entry is used for TRAP receiving purposes
    config.addV3User(
        snmpEngine, 'usr-sha-aes128',
        config.usmHMACSHAAuthProtocol, 'authkey1',
        config.usmAesCfb128Protocol, 'privkey1',
        securityEngineId=v2c.OctetString(hexValue='8000000001020304')
    )

    # Callback function for receiving notifications
    # noinspection PyUnusedLocal,PyUnusedLocal,PyUnusedLocal
    def cbFun(snmpEngine, stateReference, contextEngineId, contextName,
              varBinds, cbCtx):
        print('Notification from ContextEngineId "%s", ContextName "%s"' % (contextEngineId.prettyPrint(),
                                                                            contextName.prettyPrint()))
        for name, val in varBinds:
            print('%s = %s' % (name.prettyPrint(), val.prettyPrint()))

    # Register SNMP Application at the SNMP engine
    ntfrcv.NotificationReceiver(snmpEngine, cbFun)

    snmpEngine.transportDispatcher.jobStarted(1)  # this job would never finish

    # Run I/O dispatcher which would receive queries and send confirmations
    try:
        snmpEngine.transportDispatcher.runDispatcher()
    except:
        snmpEngine.transportDispatcher.closeDispatcher()
        raise

`Download` script.

See also: library reference.