Transport tweaks

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.

Using multiple network transports

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 IPv6/UDP, listening at [::1]:162
  • print received data on stdout

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

$ snmptrap -v1 -c public 127.0.0.1 1.3.6.1.4.1.20408.4.1.1.2 127.0.0.1 1 1 123 1.3.6.1.2.1.1.1.0 s test
$ snmptrap -v2c -c public udp6:[::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 127.0.0.1 123 1.3.6.1.6.3.1.1.5.1
from pysnmp.entity import engine, config
from pysnmp.carrier.asyncore.dgram import udp, udp6
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
config.addTransport(
    snmpEngine,
    udp.domainName,
    udp.UdpTransport().openServerMode(('127.0.0.1', 162))
)

# UDP over IPv6
config.addTransport(
    snmpEngine,
    udp6.domainName,
    udp6.Udp6Transport().openServerMode(('::1', 162))
)

# 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.

Receive notifications noting peer address

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
  • use observer facility to pull lower-level request details from SNMP engine
  • 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
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))
)

# SNMPv1/2c setup

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


# Callback function for receiving notifications
# noinspection PyUnusedLocal,PyUnusedLocal
def cbFun(snmpEngine, stateReference, contextEngineId, contextName,
          varBinds, cbCtx):
    # Get an execution context...
    execContext = snmpEngine.observer.getExecutionContext(
        'rfc3412.receiveMessage:request'
    )

    # ... and use inner SNMP engine data to figure out peer address
    print('Notification from %s, ContextEngineId "%s", ContextName "%s"' % ('@'.join([str(x) for x in execContext['transportAddress']]),
                                                                            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.