Evaluating NOTIFICATION-TYPE¶
SNMP SMI defines notifications as a TRAP or INFORM PDU containing the indication of type (snmpTrapOID) and a set of MIB variables (Managed Objects Instances) fetched from Agent’s MIB at the moment of notification.
Consequently, sending specific NOTIFICATION-TYPE implies including certain set of OIDs into PDU. PySNMP offers this facility through NotificationType class.
Sending notification with OBJECT’s¶
Send SNMP TRAP notification using the following options:
- SNMPv2c
- with community name ‘public’
- over IPv4/UDP
- send TRAP notification
- to a Manager at 104.236.166.95:162
- with TRAP ID IF-MIB::ifLink as MIB symbol
The IF-MIB::ifLink NOTIFICATION-TYPE implies including four other var-binds into the notification message describing the incident occurred. These var-binds are: IF-MIB::ifIndex.”x” IF-MIB::ifAdminStatus.”x” IF-MIB::ifOperStatus.”x” IF-MIB::ifDescr.”x”
Where “x” is MIB table index (instance index).
Functionally similar to:
from pysnmp.entity import engine, config
from pysnmp.carrier.asyncore.dgram import udp
from pysnmp.entity.rfc3413 import ntforg
from pysnmp.smi import rfc1902, view
#
# Here we fill in some values for Managed Objects Instances (invoked
# later while building TRAP message) by NOTIFICATION-TYPE macro evaluation.
# In real Agent app, these values should already be initialized during
# Agent runtime.
#
instanceIndex = (1,)
objects = {
('IF-MIB', 'ifIndex'): instanceIndex[0],
('IF-MIB', 'ifAdminStatus'): 'up',
('IF-MIB', 'ifOperStatus'): 'down',
('IF-MIB', 'ifDescr'): 'eth0'
}
# Create SNMP engine instance
snmpEngine = engine.SnmpEngine()
# MIB view controller is used for MIB lookup purposes
mibViewController = view.MibViewController(snmpEngine.getMibBuilder())
# SecurityName <-> CommunityName mapping
config.addV1System(snmpEngine, 'my-area', 'public', transportTag='all-my-managers')
# Specify security settings per SecurityName (SNMPv2c -> 1)
config.addTargetParams(snmpEngine, 'my-creds', 'my-area', 'noAuthNoPriv', 1)
# Setup transport endpoints and bind it with security settings yielding
# a target name:
# UDP/IPv4
config.addTransport(
snmpEngine,
udp.DOMAIN_NAME,
udp.UdpSocketTransport().openClientMode()
)
config.addTargetAddr(
snmpEngine, 'my-nms-1',
udp.DOMAIN_NAME, ('104.236.166.95', 162),
'my-creds',
tagList='all-my-managers'
)
# Specify what kind of notification should be sent (TRAP or INFORM),
# to what targets (chosen by tag) and what filter should apply to
# the set of targets (selected by tag)
config.addNotificationTarget(
snmpEngine, 'my-notification', 'my-filter', 'all-my-managers', 'trap'
)
# Allow NOTIFY access to Agent's MIB by this SNMP model (2), securityLevel
# and SecurityName
config.addContext(snmpEngine, '')
config.addVacmUser(snmpEngine, 2, 'my-area', 'noAuthNoPriv', (), (), (1, 3, 6))
# *** SNMP engine configuration is complete by this line ***
# Create Notification Originator App instance.
ntfOrg = ntforg.NotificationOriginator()
# Build and submit notification message to dispatcher
ntfOrg.sendVarBinds(
snmpEngine,
'my-notification', # notification targets
None, '', # contextEngineId, contextName
rfc1902.NotificationType(
rfc1902.ObjectIdentity('IF-MIB', 'linkUp'),
instanceIndex=instanceIndex,
objects=objects
).resolveWithMib(mibViewController)
)
print('Notification is scheduled to be sent')
# Run I/O dispatcher which would send pending message and process response
snmpEngine.transportDispatcher.runDispatcher()
Download
script.
See also: library reference.