Enabling SNMP v3 – Part 1: Cisco IOS Devices – Disable SNMP v1 and SNMP v2c

2. Disable SNMP v1 and SNMP v2C

CiscoTest#show snmp group 
groupname: ILMI                             security model:v1 
contextname: <no context specified>         storage-type: permanent
readview : *ilmi                            writeview: *ilmi                           
notifyview: <no notifyview specified>       
row status: active

groupname: ILMI                             security model:v2c 
contextname: <no context specified>         storage-type: permanent
readview : *ilmi                            writeview: *ilmi                           
notifyview: <no notifyview specified>       
row status: active

groupname: SNMPv3-RO                        security model:v3 priv 
contextname: <no context specified>         storage-type: nonvolatile
readview : ReadView-All                     writeview: <no writeview specified>        
notifyview: <no notifyview specified>       
row status: active      access-list: snmp-Allow

groupname: SNMPv3-RW                        security model:v3 priv 
contextname: <no context specified>         storage-type: nonvolatile
readview : ReadView-All                     writeview: WriteView-All                   
notifyview: <no notifyview specified>       
row status: active      access-list: snmp-Allow

groupname: NetService-RO                    security model:v3 priv 
contextname: <no context specified>         storage-type: nonvolatile
readview : <no readview specified>          writeview: <no writeview specified>        
notifyview: *tv.FFFFFFFF.FFFFFFFF.FFFFFFFF.F
row status: active

CiscoTest(config)#no snmp-server group ILMI v1
CiscoTest(config)#no snmp-server group ILMI v2c
CiscoTest(config)#do sh snmp group
groupname: SNMPv3-RO                        security model:v3 priv 
contextname: <no context specified>         storage-type: nonvolatile
readview : ReadView-All                     writeview: <no writeview specified>        
notifyview: <no notifyview specified>       
row status: active      access-list: snmp-Allow

groupname: SNMPv3-RW                        security model:v3 priv 
contextname: <no context specified>         storage-type: nonvolatile
readview : ReadView-All                     writeview: WriteView-All                   
notifyview: <no notifyview specified>       
row status: active      access-list: snmp-Allow

groupname: NetService-RO                    security model:v3 priv 
contextname: <no context specified>         storage-type: nonvolatile
readview : <no readview specified>          writeview: <no writeview specified>        
notifyview: *tv.FFFFFFFF.FFFFFFFF.FFFFFFFF.F
row status: active

Unfortunately those groups will come back after system rebooted. Best way is to remove them from system view by following commands:

snmp-server view *ilmi system excluded
snmp-server view *ilmi atmForumUni excluded
snmp-server view v1default iso excluded

R-Test-Lab#show snmp view
*ilmi system – excluded nonvolatile active
*ilmi atmForumUni – excluded nonvolatile active
cac_view pimMIB – included read-only active
cac_view msdpMIB – included read-only active
cac_view interfaces – included read-only active
cac_view ip – included read-only active
cac_view ospf – included read-only active
cac_view bgp – included read-only active
cac_view dot1dBridge – included read-only active
cac_view ifMIB – included read-only active
cac_view nhrpMIB – included read-only active
cac_view ipMRouteStdMIB – included read-only active
cac_view igmpStdMIB – included read-only active
cac_view ipForward – included read-only active
cac_view ipTrafficStats – included read-only active
cac_view ospfTrap – included read-only active
cac_view sysUpTime.0 – included read-only active
cac_view ciscoPingMIB – included read-only active
cac_view ciscoIpSecFlowMonitorMIB – included read-only active
cac_view ciscoIpSecPolMapMIB – included read-only active
cac_view ciscoPimMIB – included read-only active
cac_view ciscoMgmt.187 – included read-only active
cac_view ciscoIfExtensionMIB – included read-only active
cac_view ciscoEigrpMIB – included read-only active
cac_view ciscoCefMIB – included read-only active
cac_view ciscoNhrpExtMIB – included read-only active
cac_view ciscoIpMRouteMIB – included read-only active
cac_view ciscoIPsecMIB – included read-only active
cac_view cospf – included read-only active
cac_view ciscoExperiment.101 – included read-only active
cac_view ciscoIetfIsisMIB – included read-only active
cac_view ciscoIetfBfdMIB – included read-only active
cac_view ifIndex – included read-only active
cac_view ifDescr – included read-only active
cac_view ifType – included read-only active
cac_view ifAdminStatus – included read-only active
cac_view ifOperStatus – included read-only active
cac_view snmpTraps.3 – included read-only active
cac_view snmpTraps.4 – included read-only active
cac_view snmpTrapOID.0 – included read-only active
cac_view internet.6.3.1.1.4.3.0 – included read-only active
cac_view lifEntry.20 – included read-only active
cac_view cciDescriptionEntry.1 – included read-only active
v1default iso – excluded nonvolatile active
v1default internet.6.3.15 – excluded permanent active
v1default internet.6.3.16 – excluded permanent active
v1default internet.6.3.18 – excluded permanent active
v1default ciscoMgmt.394 – excluded permanent active
v1default ciscoMgmt.395 – excluded permanent active
v1default ciscoMgmt.399 – excluded permanent active
v1default ciscoMgmt.400 – excluded permanent active