Cisco Catalyst 4500 Series, Software Configuration Manual

Page: 1814 / 2086

72-6
Catalyst 4500 Series Switch, Cisco IOS Software Configuration Guide - Cisco IOS XE 3.9.xE and IOS 15.2(5)Ex
Chapter 72 Configuring SNMP
Configuring SNMP
SNMP Configuration Guidelines
An SNMP group is a table that maps SNMP users to SNMP views. An SNMP user is a member of an
SNMP group. An SNMP host is the recipient of an SNMP trap operation. An SNMP engine ID is a name
for the local or remote SNMP engine.
When configuring SNMP, follow these guidelines:
• When configuring an SNMP group, do not specify a notify view. The snmp-server host global
configuration command autogenerates a notify view for you and then adds it to the group associated
with that user. Modifying the group's notify view affects all users associated with that group. For
information about when you should configure notify views, see the
Cisco IOS Configuration
Fundamentals Command Reference, Release 12.2 .
•
To configure a remote user, specify the IP address or port number for the remote SNMP agent of the
device where you reside.
•
Before you configure remote users for a particular agent, configure the SNMP engine ID, using the
snmp-server engineID global configuration with the remote option. The remote agent's SNMP
engine ID and user password are used to compute the authentication and privacy digests. If you do
not configure the remote engine ID first, the configuration command fails.
•
When configuring SNMP informs, you need to configure the SNMP engine ID for the remote agent
in the SNMP database before you can send proxy requests or informs to it.
•
If a local user is not associated with a remote host, the switch does not send informs for the auth
(authNoPriv) and the priv (authPriv) authentication levels.
•
Changing the value of the SNMP engine ID has important side effects. A user's password (entered
on the command line) is converted to an MD5 or SHA security digest based on the password and the
local engine ID. The command-line password is then destroyed, as required by RFC 2274. Because
of this deletion, if the value of the engine ID changes, the security digests of SNMPv3 users become
invalid, and you need to reconfigure SNMP users by using the
snmp-server user username global
configuration command. Similar restrictions require the reconfiguration of community strings when
the engine ID changes.
Table 72-2 Default SNMP Configuration
Feature Default Setting
SNMP agent Enabled
SNMP trap receiver None configured
SNMP traps None enabled except the trap for TCP connections ( tty )
SNMP version If no version keyword is present, the default is Version 1.
SNMPv3 authentication If no keyword is entered, the default is the noauth (noAuthNoPriv)
security level.
SNMP notification type If no type is specified, all notifications are sent.