# Transport tweaks

## Listen on multiple network interfaces

Listen and respond to SNMP GET/SET/GETNEXT/GETBULK queries with the following options:

- SNMPv2c

- with SNMP community “public”

- allow access to SNMPv2-MIB objects (1.3.6.1.2.1)

- over IPv4/UDP, listening at 127.0.0.1:161 and 127.0.0.2:161 interfaces

- using Twisted framework for network transport

Either of the following Net-SNMP commands will walk this Agent:

$ snmpwalk -v2c -c public 127.0.0.1 .1.3.6
$ snmpwalk -v2c -c public 127.0.0.2 .1.3.6

    from twisted.internet import reactor
    from pysnmp.entity import engine, config
    from pysnmp.entity.rfc3413 import cmdrsp, context
    from pysnmp.carrier.twisted.dgram import udp

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

    # Transport setup

    # UDP over IPv4 at 127.0.0.1:161
    config.addTransport(
        snmpEngine,
        udp.domainName + (1,),
        udp.UdpTwistedTransport().openServerMode(('127.0.0.1', 161))
    )

    # UDP over IPv4 at 127.0.0.2:161
    config.addTransport(
        snmpEngine,
        udp.domainName + (2,),
        udp.UdpTwistedTransport().openServerMode(('127.0.0.2', 161))
    )

    # SNMPv2c setup

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

    # Allow full MIB access for this user / securityModels at VACM
    config.addVacmUser(snmpEngine, 2, 'my-area', 'noAuthNoPriv', (1, 3, 6, 1, 2, 1), (1, 3, 6, 1, 2, 1))

    # Get default SNMP context this SNMP engine serves
    snmpContext = context.SnmpContext(snmpEngine)

    # Register SNMP Applications at the SNMP engine for particular SNMP context
    cmdrsp.GetCommandResponder(snmpEngine, snmpContext)
    cmdrsp.SetCommandResponder(snmpEngine, snmpContext)
    cmdrsp.NextCommandResponder(snmpEngine, snmpContext)
    cmdrsp.BulkCommandResponder(snmpEngine, snmpContext)

    # Run Twisted main loop
    reactor.run()

`Download` script.

See also: library reference.