Transport tweaks

Custom request timeout

Send SNMP GET request using the following options:

  • with SNMPv2c, community ‘public’
  • over IPv4/UDP
  • to an Agent at demo.snmplabs.com:161
  • for an OID in string form
  • use custom timeout and request retries values

Transport timing settings (maximum number of request retries and individual request timeout in seconds) can be set on a per-target basis as explained by the code that follows.

Keep in mind that while timeout value can be specified in fractions of a second, default pysnmp timer resolution is quite low (about 0.5 sec) so there’s no much point in using timeouts which is not a multiple of 0.5 Internal timer can be programmatically adjusted to finer resolution if needed.

If retries value is set to 0, pysnmp will issue a single request. Even if no response arrives, there will be no retry. Likewise, retries=1 means one initial request plus one retry.

Functionally similar to:

$ snmpget -v1 -c public -t 2 -r 0 demo.snmplabs.com 1.3.6.1.2.1.1.1.0
from pysnmp.hlapi import *

errorIndication, errorStatus, errorIndex, varBinds = next(
    getCmd(SnmpEngine(),
           CommunityData('public'),
           UdpTransportTarget(
               ('demo.snmplabs.com', 161), timeout=2.0, retries=0
           ),
           ContextData(),
           ObjectType(ObjectIdentity('1.3.6.1.2.1.1.1.0')))
)

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]))

Download script.

GET over IPv6

Send SNMP GET request using the following options:

  • with SNMPv3 with user ‘usr-md5-des’, MD5 auth and DES privacy protocols
  • over IPv6/UDP
  • to an Agent at [::1]:161
  • for three OIDs in string form

Functionally similar to:

$ snmpget -v3 -l authPriv -u usr-md5-des -A authkey1 -X privkey1 udp6:[::1]:161 1.3.6.1.2.1.1.1.0 1.3.6.1.2.1.1.2.0 1.3.6.1.2.1.1.3.0
from pysnmp.hlapi import *

errorIndication, errorStatus, errorIndex, varBinds = next(
    getCmd(SnmpEngine(),
           UsmUserData('usr-md5-des', 'authkey1', 'privkey1'),
           Udp6TransportTarget(('::1', 161)),
           ContextData(),
           ObjectType(ObjectIdentity('1.3.6.1.2.1.1.1.0')),
           ObjectType(ObjectIdentity('1.3.6.1.2.1.1.2.0')),
           ObjectType(ObjectIdentity('1.3.6.1.2.1.1.3.0')))
)

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]))

Download script.

See also: library reference.