Synchronous SNMPΒΆ

This chapter illustrates various uses of the synchronous high-level programming interface to some of Standard SNMP Applications, as defined in RFC3413.

Note

The following examples involve creating Python iterator, the next() call is used to invoke iterator just once.

In most examples approximate analogues of well known Net-SNMP snmp* tools command line options are shown. That may help those readers who, by chance are familiar with Net-SNMP tools, better understanding what example code doe

Here’s a quick example on a simple SNMP GET by high-level API:

  • with SNMPv1, community ‘public’
  • over IPv4/UDP
  • to an Agent at demo.snmplabs.com:161
  • for two instances of SNMPv2-MIB::sysDescr.0 MIB object,
from pysnmp.hlapi import *

errorIndication, errorStatus, errorIndex, varBinds = next(
    getCmd(SnmpEngine(),
           CommunityData('public', mpModel=0),
           UdpTransportTarget(('demo.snmplabs.com', 161)),
           ContextData(),
           ObjectType(ObjectIdentity('SNMPv2-MIB', 'sysDescr', 0)))
)

if errorIndication:
    print(errorIndication)
elif errorStatus:
    print('%s at %s' % (errorStatus.prettyPrint(),
                        errorIndex and varBinds[int(errorIndex) - 1][0] or '?'))
else:
    for varBind in varBinds:
        print(' = '.join([x.prettyPrint() for x in varBind]))

To make use of SNMPv3 and USM, the following code performs a series of SNMP GETNEXT operations effectively fetching a table of SNMP variables from SNMP Agent:

  • with SNMPv3, user ‘usr-md5-none’, MD5 authentication, no privacy
  • over IPv4/UDP
  • to an Agent at demo.snmplabs.com:161
  • for all OIDs in IF-MIB
from pysnmp.hlapi import *

for (errorIndication,
     errorStatus,
     errorIndex,
     varBinds) in nextCmd(SnmpEngine(),
                          UsmUserData('usr-md5-none', 'authkey1'),
                          UdpTransportTarget(('demo.snmplabs.com', 161)),
                          ContextData(),
                          ObjectType(ObjectIdentity('IF-MIB'))):

    if errorIndication:
        print(errorIndication)
        break
    elif errorStatus:
        print('%s at %s' % (errorStatus.prettyPrint(),
                            errorIndex and varBinds[int(errorIndex) - 1][0] or '?'))
        break
    else:
        for varBind in varBinds:
            print(' = '.join([x.prettyPrint() for x in varBind]))

More examples on Command Generator API usage follow.

Sending SNMP TRAP’s and INFORM’s is as easy with PySNMP library. The following code sends SNMP TRAP:

  • SNMPv1
  • with community name ‘public’
  • over IPv4/UDP
  • send TRAP notification
  • with Generic Trap #1 (warmStart) and Specific Trap 0
  • with default Uptime
  • with default Agent Address
  • with Enterprise OID 1.3.6.1.4.1.20408.4.1.1.2
  • include managed object information ‘1.3.6.1.2.1.1.1.0’ = ‘my system’
from pysnmp.hlapi import *

errorIndication, errorStatus, errorIndex, varBinds = next(
    sendNotification(
        SnmpEngine(),
        CommunityData('public', mpModel=0),
        UdpTransportTarget(('demo.snmplabs.com', 162)),
        ContextData(),
        'trap',
        NotificationType(
            ObjectIdentity('1.3.6.1.6.3.1.1.5.2')
        ).addVarBinds(
            ('1.3.6.1.6.3.1.1.4.3.0', '1.3.6.1.4.1.20408.4.1.1.2'),
            ('1.3.6.1.2.1.1.1.0', OctetString('my system'))
        )
    )
)

if errorIndication:
    print(errorIndication)

More examples on Notification Originator API usage follow.

More sophisticated or less popular SNMP operations can still be performed with PySNMP through its Native API to Standard SNMP Applications.