SNMP

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Functional Areas

Data Definition - syntax conventions; Structure of Management Information (SMI)
MIBs - internet standards and vendor-proprietary
Protocols - messages used to exchange management data
Security & Administration - secure the exchange

Versions

1 - SMIv1; simple authentication for communities; MIB-I
2 - SMIv2; removed requirement for communities; GetBulk and Inform messages; MIB-II
2c - SNMPv1 style communities with SNMPv2
3 - better security

Protocol Messages

Get - manager; request for single variable
GetNext - manager; request next MIB leave variable in the MIB tree; used for MIB walking
GetBulk - version 2; manager; request multiple MIB variables
Response - no response; agent; respond to information in set and get requests
Set - manager; tell agent to set variable
Trap - no response; agent; tells agent to send unsolicited information to manager
Inform - version 2; manager; exchange data between managers

Remote Monitoring (RMON MIB)

capturing packets
calculate statistics
monitor threshold for specific MIB variables

Security

SNMPv3 uses authentication and encryption
md5 and sha to create digest for each message
DES (AES suggested but not part of original standard)

Configuring

config# access-list 33 permit 192.168.1.0 0.0.0.255
config# snmp-server community public RW 33
config# snmp-server location B1
config# snmp-server contact routerhelpdesk@mail.local
config# snmp-server chassis-id 1511_AccessServer_Canadice
config# snmp-server enable traps snmp
config# snmp-server enable traps hsrp
config# snmp-server enable traps config
config# snmp-server enable traps entity
config# snmp-server enable traps bgp
config# snmp-server enable traps rsvp
config# snmp-server enable traps frame-relay
config# snmp-server enable traps rtr
config# snmp-server host 192.168.1.100 public