Re: [pysnmp-users] PySNMP v3 Notification receiver

[rajesh c. <cxr...@gm...>]

Hi,

I have PySNMP notification receiver for SNMP V3 traps as below...

Instead of localhost IP , I have My VM ip -----> for this scenario, I am
not receiving any traps if generate one from outside the VM(I am using
snmptrap command from another machine) but I can see SNMP data when I do
tcpdump on VM eth0. If I generate trap on same machine(My VM) I can see
trap data via PySNMP trap receiver script. I have no issues with network
connectivity and FW is not blocking any of My data.

Please help me ASAP

from pysnmp.entity import engine, config
from pysnmp.carrier.asynsock.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.addSocketTransport(
    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, contextEngineId: 8000000001020304
# this USM entry is used for TRAP receiving purposes
config.addV3User(
    snmpEngine, 'usr-md5-des',
    config.usmHMACMD5AuthProtocol, 'authkey1',
    config.usmDESPrivProtocol, 'privkey1',
    contextEngineId=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, contextEngineId: 8000000001020304
# this USM entry is used for TRAP receiving purposes
config.addV3User(
    snmpEngine, 'usr-md5-none',
    config.usmHMACMD5AuthProtocol, 'authkey1',
    contextEngineId=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, contextEngineId: 8000000001020304
# this USM entry is used for TRAP receiving purposes
config.addV3User(
    snmpEngine, 'usr-sha-aes128',
    config.usmHMACSHAAuthProtocol, 'authkey1',
    config.usmAesCfb128Protocol, 'privkey1',
    contextEngineId=v2c.OctetString(hexValue='8000000001020304')
)

# Callback function for receiving notifications
def cbFun(snmpEngine,
          stateReference,
          contextEngineId, contextName,
          varBinds,
          cbCtx):
    print('Notification received, 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