Cisco Industrial Ethernet 4000, 4010 and 5000 Switch Software. Configuration Guide (2022)

Configuring System Message Logging

Information About System Message Logging

Table 50

Level Keywords

Level Keyword

Level

Description

Syslog Definition

emergencies

System unstable

LOG_EMERG

alerts

Immediate action needed

LOG_ALERT

critical

Critical conditions

LOG_CRIT

errors

Error conditions

LOG_ERR

warnings

Warning conditions

LOG_WARNING

notifications

Normal but significant condition

LOG_NOTICE

informational

Informational messages only

LOG_INFO

debugging

Debugging messages

LOG_DEBUG

The software generates these categories of messages:

Error messages about software or hardware malfunctions, displayed at levels warnings through emergencies.

These types of messages mean that the functionality of the switch is affected.

Output from the debug commands, displayed at the debugging level. Debug commands are typically used only by

the Technical Assistance Center.

Interface up or down transitions and system restart messages, displayed at the notifications level. This message is

only for information; switch functionality is not affected.

Configuring UNIX Syslog Servers

The next sections describe how to configure the UNIX server syslog daemon and how to define the UNIX system logging

facility.

Logging Messages to a UNIX Syslog Daemon

Before you can send system log messages to a UNIX syslog server, you must configure the syslog daemon on a UNIX

server. This procedure is optional.

Note: Some recent versions of UNIX syslog daemons no longer accept by default syslog packets from the network. If this

is the case with your system, use the UNIX man syslogd command to decide what options must be added to or removed

from the syslog command line to enable logging of remote syslog messages.

1. Add a line such as the following to the file /etc/syslog.conf:

local7.debug /usr/adm/logs/cisco.log

The local7 keyword specifies the logging facility to be used. The debug keyword specifies the syslog level. The syslog

daemon sends messages at this level or at a more severe level to the file specified in the next field. The file must already

exist, and the syslog daemon must have permission to write to it.

2. Create the log file by entering these commands at the UNIX shell prompt:

$ touch /var/log/cisco.log

$ chmod 666 /var/log/cisco.log

3. Make sure the syslog daemon reads the new changes:

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Configuring System Message Logging

Information About System Message Logging

$ kill -HUP `cat /etc/syslog.pid`

For more information, see the man syslog.conf and man syslogd commands on your UNIX system.

Table 51 on page 548 lists the UNIX system facilities supported by the software. For more information about these

facilities, consult the operator’s manual for your UNIX operating system.

Table 51

UNIX System Facilities

Facility Type Keyword

Description

auth

Authorization system

cron

Cron facility

daemon

System daemon

kern

Kernel

local0-7

Locally defined messages

lpr

Line printer system

mail

Mail system

news

USENET news

sys9-14

System use

syslog

System log

user

User process

uucp

UNIX-to-UNIX copy system

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Configuring System Message Logging

How to Configure System Message Logging

Default System Message Logging Configuration

Feature

Default Setting

System message logging to the console

Enabled.

Console severity

Debugging (and numerically lower levels).

Logging file configuration

No filename specified.

Logging buffer size

4096 bytes.

Logging history size

1 message.

Time stamps

Disabled.

Synchronous logging

Disabled.

Logging server

Disabled.

Syslog server IP address

None configured.

Configuration change logger

Disabled.

Server facility

Local7.

Server severity

Informational (and numerically lower levels).

How to Configure System Message Logging

Disabling Message Logging

Message logging is enabled by default. It must be enabled to send messages to any destination other than the console.

When enabled, log messages are sent to a logging process, which logs messages to designated locations

asynchronously to the processes that generated the messages.

Disabling the logging process can slow down the switch because a process must wait until the messages are written to

the console before continuing. When the logging process is disabled, messages appear on the console as soon as they

are produced, often appearing in the middle of command output.

Command

Purpose

configure terminal

Enters global configuration mode.

no logging console

Disables message logging.

end

Returns to privileged EXEC mode.

Setting the Message Display Destination Device

If message logging is enabled, you can send messages to specific locations in addition to the console. Beginning in

privileged EXEC mode, use one or more of the following commands to specify the locations that receive messages:

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Configuring System Message Logging

How to Configure System Message Logging

Command

Purpose

configure terminal

Enters global configuration mode.

logging buffered [size]

Logs messages to an internal buffer on the switch. The range is 4096 to

2147483647 bytes. The default buffer size is 4096 bytes.

If the switch fails, the log file is lost unless you had previously saved it to

flash memory. See Step 4.

Note: Do not make the buffer size too large because the switch could run

out of memory for other tasks. Use the show memory privileged EXEC

command to view the free processor memory on the switch. However,

this value is the maximum available, and the buffer size should not be set

to this amount.

logging host

Logs messages to a UNIX syslog server host.

host—Specifies the name or IP address of the host to be used as the

syslog server.

To build a list of syslog servers that receive logging messages, enter this

command more than once.

logging file flash:filename

Stores log messages in a file in flash memory.

[max-file-size [min-file-size]]

[severity-level-number | type]

filename—Enters the log message filename.

(Optional) max-file-size—Specifies the maximum logging file size.

The range is 4096 to 2147483647. The default is 4096 bytes.

(Optional) min-file-size—Specifies the minimum logging file size. The

range is 1024 to 2147483647. The default is 2048 bytes.

(Optional) severity-level-number | type—Specifies either the logging

severity level or the logging type. The severity range is 0 to 7. By

default, the log file receives debugging messages and numerically

lower levels.

end

Returns to privileged EXEC mode.

terminal monitor

Logs messages to a nonconsole terminal during the current session.

Terminal parameter-setting commands are set locally and do not remain

in effect after the session has ended. You must perform this step for each

session to see the debugging messages.

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Configuring System Message Logging

How to Configure System Message Logging

Synchronizing Log Messages

Command

Purpose

configure terminal

Enters global configuration mode.

line [console | vty] line-number

Specifies the line to be configured for synchronous logging of

[ending-line-number]

messages.

Use the console keyword for configurations that occur through

the switch console port.

Use the line vty line-number command to specify which vty

lines are to have synchronous logging enabled. You use a vty

connection for configurations that occur through a Telnet

session. The range of line numbers is from 0 to 15.

You can change the setting of all 16 vty lines at once by entering:

line vty 0 15

Or you can change the setting of the single vty line being used for

your current connection. For example, to change the setting for vty

line 2, enter:

line vty 2

When you enter this command, the mode changes to line

configuration.

logging synchronous [level [severity-level |

Enables synchronous logging of messages.

all] | limit number-of-buffers]

(Optional) level severity-level—Specifies the message severity

level. Messages with a severity level equal to or higher than this

value are printed asynchronously. Low numbers mean greater

severity and high numbers mean lesser severity. The default is 2.

(Optional) level all—Specifies that all messages are printed

asynchronously regardless of the severity level.

(Optional) limit number-of-buffers—Specifies the number of

buffers to be queued for the terminal after which new messages

are dropped. The range is 0 to 2147483647. The default is 20.

end

Returns to privileged EXEC mode.

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Configuring System Message Logging

How to Configure System Message Logging

Enabling and Disabling Time Stamps on Log Messages

Command

Purpose

configure terminal

Enters global configuration mode.

service timestamps log uptime

Enables log time stamps.

The first command enables time stamps on log messages,

showing the time since the system was rebooted.

service timestamps log datetime [msec]

[localtime] [show-timezone]

The second command enables time stamps on log

messages. Depending on the options selected, the time

stamp can include the date, time in milliseconds relative to

the local time-zone, and the time zone name.

end

Returns to privileged EXEC mode.

Enabling and Disabling Sequence Numbers in Log Messages

Because there is a chance that more than one log message can have the same time stamp, you can display messages

with sequence numbers so that you can unambiguously see a single message. By default, sequence numbers in log

messages are not displayed.

Command

Purpose

configure terminal

Enters global configuration mode.

service sequence-numbers

Enables sequence numbers.

end

Returns to privileged EXEC mode.

Defining the Message Severity Level

You can limit messages displayed to the selected device by specifying the severity level of the message, which are

described in Table 2.

Command

Purpose

configure terminal

Enters global configuration mode.

logging console level

Limits messages logged to the console.

By default, the console receives debugging messages and numerically

lower levels.

logging monitor level

Limits messages logged to the terminal lines.

By default, the terminal receives debugging messages and numerically

lower levels.

logging trap level

Limits messages logged to the syslog servers.

By default, syslog servers receive informational messages and

numerically lower levels.

end

Returns to privileged EXEC mode.

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Configuring System Message Logging

How to Configure System Message Logging

Limiting Syslog Messages Sent to the History Table and to SNMP

If you enabled syslog message traps to be sent to an SNMP network management station by using the snmp-server

enable trap global configuration command, you can change the level of messages sent and stored in the switch history

table. You also can change the number of messages that are stored in the history table.

Messages are stored in the history table because SNMP traps are not guaranteed to reach their destination. By default,

one message of the level warning and numerically lower levels are stored in the history table even if syslog traps are not

enabled.

When the history table is full (it contains the maximum number of message entries specified with the logging history

size global configuration command), the oldest message entry is deleted from the table to allow the new message entry

to be stored.

Command

Purpose

configure terminal

Enters global configuration mode.

logging history level

Changes the default level of syslog messages stored in the history file and

sent to the SNMP server.

By default, warnings, errors, critical, alerts, and emergencies messages

are sent.

logging history size number

Specifies the number of syslog messages that can be stored in the history

table.

The default is to store one message. The range is 0 to 500 messages.

end

Returns to privileged EXEC mode.

Enabling the Configuration-Change Logger

You can enable a configuration logger to keep track of configuration changes made with the command-line interface

(CLI). When you enter the logging enable configuration-change logger configuration command, the log records the

session, the user, and the command that was entered to change the configuration. You can configure the size of the

configuration log from 1 to 1000 entries (the default is 100).

Command

Purpose

configure terminal

Enters global configuration mode.

Related Topic

Document Title

Cisco IOS basic commands

Cisco IOS Configuration Fundamentals Command Reference

Cisco IOS system management commands

Syslog server configuration steps

Configuring the UNIX System Logging Facility, page 553

Standards

Title

No new or modified standards are supported by this

—

feature, and support for existing standards has not

been modified by this feature.

MIBs

MIBs Link

—

To locate and download MIBs using Cisco IOS XR software, use the

Cisco MIB Locator found at the following URL and choose a platform

under the Cisco Access Products menu:

http://cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml

RFCs

Title

No new or modified RFCs are supported by this

—

feature, and support for existing RFCs has not been

modified by this feature.

Technical Assistance

Description

Link

The Cisco Technical Support website contains

http://www.cisco.com/techsupport

thousands of pages of searchable technical content,

including links to products, technologies, solutions,

technical tips, and tools. Registered Cisco.com users

can log in from this page to access even more content.

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Configuring SNMP

Prerequisites for SNMP

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.

If the switch starts and the switch startup configuration has at least one snmp-server global configuration

command, the SNMP agent is enabled.

When configuring an SNMP group, do not specify a notify view. The snmp-server host global configuration

command autogenerates a notify view for the user and then adds it to the group associated with that user. Modifying

the group's notify view affects all users associated with that group. See the Cisco IOS Network Management

Command Reference for information about when you should configure notify views.

To configure a remote user, specify the IP address or port number for the remote SNMP agent of the device where

the user resides.

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.

Restrictions for SNMP

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 implications. 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.

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Configuring SNMP

Information About SNMP

SNMP

The Simple Network Management Protocol (SNMP) is an application-layer protocol that provides a message format for

communication between managers and agents. The SNMP system consists of an SNMP manager, an SNMP agent, and

a MIB. The SNMP manager can be part of a network management system (NMS) such as CiscoWorks. The agent and

MIB reside on the switch. To configure SNMP on the switch, you define the relationship between the manager and the

agent.

The SNMP agent contains MIB variables whose values the SNMP manager can request or change. A manager can get a

value from an agent or store a value into the agent. The agent gathers data from the MIB, the repository for information

about device parameters and network data. The agent can also respond to a manager’s requests to get or set data.

An agent can send unsolicited traps to the manager. Traps are messages alerting the SNMP manager to a condition on

the network. Traps can mean improper user authentication, restarts, link status (up or down), MAC address tracking,

closing of a TCP connection, loss of connection to a neighbor, or other significant events.

SNMP Versions

This software release supports these SNMP versions:

SNMPv1—The Simple Network Management Protocol, a Full Internet Standard, defined in RFC 1157.

SNMPv2C replaces the Party-based Administrative and Security Framework of SNMPv2Classic with the

community-string-based Administrative Framework of SNMPv2C while retaining the bulk retrieval and improved

error handling of SNMPv2Classic. It has these features:

— SNMPv2—Version 2 of the Simple Network Management Protocol, a Draft Internet Standard, defined in RFCs

1902 through 1907.

— SNMPv2C—The community-string-based Administrative Framework for SNMPv2, an Experimental Internet

Protocol defined in RFC 1901.

SNMPv3—Version 3 of the SNMP is an interoperable standards-based protocol defined in RFCs 2273 to 2275.

SNMPv3 provides secure access to devices by authenticating and encrypting packets over the network and includes

these security features:

— Message integrity—Ensures that a packet was not tampered with in transit.

— Authentication—Determines that the message is from a valid source.

— Encryption—Mixes the contents of a package to prevent it from being read by an unauthorized source.

To select encryption, enter the priv keyword. This keyword is available only when the cryptographic (encrypted)

software image is installed.

Both SNMPv1 and SNMPv2C use a community-based form of security. The community of managers able to access the

agent’s MIB is defined by an IP address access control list and password.

SNMPv2C includes a bulk retrieval mechanism and more detailed error message reporting to management stations. The

bulk retrieval mechanism retrieves tables and large quantities of information, minimizing the number of round-trips

required. The SNMPv2C improved error-handling includes expanded error codes that distinguish different kinds of error

conditions; these conditions are reported through a single error code in SNMPv1. Error return codes in SNMPv2C report

the error type.

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Configuring SNMP

Information About SNMP

SNMPv3 provides for both security models and security levels. A security model is an authentication strategy set up for

a user and the group within which the user resides. A security level is the permitted level of security within a security

model. A combination of the security level and the security model determine which security mechanism is used when

handling an SNMP packet. Available security models are SNMPv1, SNMPv2C, and SNMPv3.

Table 52 on page 559 identifies the characteristics of the different combinations of security models and levels.

Table 52

SNMP Security Models and Levels

Model

Level

Authentication

Encryption

Result

SNMPv1

noAuthNoPriv

Community string

Uses a community string match for authentication.

SNMPv2C

noAuthNoPriv

Community string

Uses a community string match for authentication.

SNMPv3

noAuthNoPriv

Username

Uses a username match for authentication.

SNMPv3

authNoPriv

Message Digest 5

Provides authentication based on the HMAC-MD5 or

(MD5) or Secure

HMAC-SHA algorithms.

Hash Algorithm

(SHA)

SNMPv3

authPriv

MD5 or SHA

Data Encryption

Provides authentication based on the HMAC-MD5 or

Standard (DES)

HMAC-SHA algorithms. Allows specifying the

or Advanced

User-based Security Model (USM) with these

Encryption

encryption algorithms:

Standard (AES)

DES 56-bit encryption in addition to

authentication based on the CBC-DES (DES-56)

standard.

3DES 168-bit encryption

AES 128-bit, 192-bit, or 256-bit encryption

You must configure the SNMP agent to use the SNMP version supported by the management station. Because an agent

can communicate with multiple managers, you can configure the software to support communications using SNMPv1,

SNMPv2C, or SNMPv3.

SNMP Manager Functions

The SNMP manager uses information in the MIB to perform the operations described in Table 53 on page 559.

Table 53

SNMP Operations

Operation

Description

get-request

Retrieves a value from a specific variable.

get-next-request

Retrieves a value from a variable within a table.¹

get-bulk-request²

Retrieves large blocks of data, such as multiple rows in a table, that would otherwise require the

transmission of many small blocks of data.

get-response

Replies to a get-request, get-next-request, and set-request sent by an NMS.

set-request

Stores a value in a specific variable.

trap

An unsolicited message sent by an SNMP agent to an SNMP manager when some event has occurred.

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Configuring SNMP

Information About SNMP

1. With this operation, an SNMP manager does not need to know the exact variable name. A sequential search is performed

to find the needed variable from within a table.

2. The get-bulk command only works with SNMPv2 or later.

SNMP Agent Functions

The SNMP agent responds to SNMP manager requests as follows:

Get a MIB variable—The SNMP agent begins this function in response to a request from the NMS. The agent retrieves

the value of the requested MIB variable and responds to the NMS with that value.

Set a MIB variable—The SNMP agent begins this function in response to a message from the NMS. The SNMP agent

changes the value of the MIB variable to the value requested by the NMS.

The SNMP agent also sends unsolicited trap messages to notify an NMS that a significant event has occurred on the

agent. Examples of trap conditions include, but are not limited to, when a port or module goes up or down, when

spanning-tree topology changes occur, and when authentication failures occur.

SNMP Community Strings

SNMP community strings authenticate access to MIB objects and function as embedded passwords. In order for the NMS

to access the switch, the community string definitions on the NMS must match at least one of the three community string

definitions on the switch.

A community string can have one of these attributes:

Read-only (RO)—Gives read access to authorized management stations to all objects in the MIB except the

community strings, but does not allow write access.

Read-write (RW)—Gives read and write access to authorized management stations to all objects in the MIB, but does

not allow access to the community strings.

When a cluster is created, the command switch manages the exchange of messages among member switches and the

SNMP application.

Using SNMP to Access MIB Variables

An example of an NMS is the CiscoWorks network management software. CiscoWorks 2000 software uses the switch

MIB variables to set device variables and to poll devices on the network for specific information. The results of a poll can

be displayed as a graph and analyzed to troubleshoot internetworking problems, increase network performance, verify

the configuration of devices, monitor traffic loads, and more.

As shown in Figure 73 on page 561, the SNMP agent gathers data from the MIB. The agent can send traps, or notification

of certain events, to the SNMP manager, which receives and processes the traps. Traps alert the SNMP manager to a

condition on the network such as improper user authentication, restarts, link status (up or down), MAC address tracking,

and so forth. The SNMP agent also responds to MIB-related queries sent by the SNMP manager in get-request,

get-next-request, and set-request format.

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Configuring SNMP

Information About SNMP

Figure 73

SNMP Network

Get-request, Get-next-request,

Network device

NMS

Get-bulk, Set-request

MIB

Get-response, traps

SNMP Manager

SNMP Agent

SNMP Notifications

SNMP allows the switch to send notifications to SNMP managers when particular events occur. SNMP notifications can

be sent as traps or inform requests. In command syntax, unless there is an option in the command to select either traps

or informs, the keyword traps refers to either traps or informs, or both. Use the snmp-server host command to specify

whether to send SNMP notifications as traps or informs.

Note: SNMPv1 does not support informs.

Traps are unreliable because the receiver does not send an acknowledgment when it receives a trap, and the sender

cannot determine if the trap was received. When an SNMP manager receives an inform request, it acknowledges the

message with an SNMP response protocol data unit (PDU). If the sender does not receive a response, the inform request

can be sent again. Because they can be resent, informs are more likely than traps to reach their intended destination.

The characteristics that make informs more reliable than traps also consume more resources in the switch and in the

network. Unlike a trap, which is discarded as soon as it is sent, an inform request is held in memory until a response is

received or the request times out. Traps are sent only once, but an inform might be resent or retried several times. The

retries increase traffic and contribute to a higher overhead on the network. Therefore, traps and informs require a

trade-off between reliability and resources. If it is important that the SNMP manager receive every notification, use inform

requests. If traffic on the network or memory in the switch is a concern and notification is not required, use traps.

SNMP ifIndex MIB Object Values

In an NMS, the IF-MIB generates and assigns an interface index (ifIndex) object value that is a unique number greater

than zero to identify a physical or a logical interface. When the switch reboots or the switch software is upgraded, the

switch uses this same value for the interface. For example, if the switch assigns a port 2 an ifIndex value of 10003, this

value is the same after the switch reboots.

The switch uses one of the values in Table 54 on page 561 to assign an ifIndex value to an interface.

Table 54

ifIndex MIB Object Values

Interface Type

ifIndex Range

SVI

1-4999

EtherChannel

5001-5048

Physical (such as Gigabit Ethernet or SFP-module interfaces) based on type

10000-14500

and port numbers

Null

10501

Loopback and Tunnel

24567 +

Note: The switch might not use sequential values within a range.

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Configuring SNMP

Information About SNMP

Community Strings

You use the SNMP community string to define the relationship between the SNMP manager and the agent. The

community string acts like a password to permit access to the agent on the switch. Optionally, you can specify one or

more of these characteristics associated with the string:

An access list of IP addresses of the SNMP managers that are permitted to use the community string to gain access

to the agent

A MIB view, which defines the subset of all MIB objects accessible to the given community

Read and write or read-only permission for the MIB objects accessible to the community

SNMP Notifications

A trap manager is a management station that receives and processes traps. Traps are system alerts that the switch

generates when certain events occur. By default, no trap manager is defined, and no traps are sent. Switches running

this Cisco IOS release can have an unlimited number of trap managers.

Note: Many commands use the word traps in the command syntax. Unless there is an option in the command to select

either traps or informs, the keyword traps refers to traps, informs, or both. Use the snmp-server host global

configuration command to specify whether to send SNMP notifications as traps or informs.

This table describes the supported switch traps (notification types). You can enable any or all of these traps and configure

a trap manager to receive them. To enable the sending of SNMP inform notifications, use the snmp-server enable traps

global configuration command combined with the snmp-server host host-addr informs global configuration command.

Table 55

Switch Notification Types

Notification Type

Description

Keyword

bridge

Generates STP bridge MIB traps.

config

Generates a trap for SNMP configuration changes.

copy-config

Generates a trap for SNMP copy configuration changes.

entity

Generates a trap for SNMP entity changes.

cpu threshold

Allows CPU-related traps.

envmon

Generates environmental monitor traps. You can enable any or all of these environmental traps: fan,

shutdown, status, supply, temperature.

errdisable

Generates a trap for an error-disabled VLAN port. You can also set a maximum trap rate per minute.

The range is from 0 to 10000; the default is 0, which means there is no rate limit.

flash

Generates SNMP FLASH notifications.

hsrp

Generates a trap for Hot Standby Router Protocol (HSRP) changes.

ipmulticast

Generates a trap for IP multicast routing changes.

mac-notification

Generates a trap for MAC address notifications.

msdp

Generates a trap for Multicast Source Discovery Protocol (MSDP) changes.

ospf

Generates a trap for Open Shortest Path First (OSPF) changes. You can enable any or all of these

traps: Cisco specific, errors, link-state advertisement, rate limit, retransmit, and state changes.

pim

Generates a trap for Protocol-Independent Multicast (PIM) changes. You can enable any or all of

these traps: invalid PIM messages, neighbor changes, and rendezvous point (RP)-mapping

changes.

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Information About SNMP

Table 55

Switch Notification Types (continued)

Notification Type

Description

Keyword

port-security

Generates SNMP port security traps. You can also set a maximum trap rate per second. The range

is from 0 to 1000; the default is 0, which means that there is no rate limit.

Note: When you configure a trap by using the notification type port-security, configure the port

security trap first, and then configure the port security trap rate:

snmp-server enable traps port-security

snmp-server enable traps port-security trap-rate rate

rtr

Generates a trap for the SNMP Response Time Reporter (RTR).

snmp

Generates a trap for SNMP-type notifications for authentication, cold start, warm start, link up or link

down.

storm-control

Generates a trap for SNMP storm control. You can also set a maximum trap rate per minute. The

range is from 0 to 1000; the default is 0 (no limit is imposed; a trap is sent at every occurrence).

stpx

Generates SNMP STP Extended MIB traps.

syslog

Generates SNMP syslog traps.

tty

Generates a trap for TCP connections. This trap is enabled by default.

vlan-membership

Generates a trap for SNMP VLAN membership changes.

vlancreate

Generates SNMP VLAN created traps.

vlandelete

Generates SNMP VLAN deleted traps.

vtp

Generates a trap for VLAN Trunking Protocol (VTP) changes.

Note: Though visible in the command-line help strings, the fru-ctrl, insertion, and removal keywords are not supported.

You can use the snmp-server host global configuration command to a specific host to receive the notification types

listed in Table 55 on page 562.

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Configuring SNMP

How to Configure SNMP

Default SNMP Settings

Feature

Default Setting

SNMP agent

Disabled¹.

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.

1. This is the default when the switch starts and the startup configuration does not have any snmp-server global

configuration commands.

How to Configure SNMP

Disabling the SNMP Agent

The no snmp-server global configuration command disables all running versions (Version 1,

Version 2C, and Version 3) on the device. No specific Cisco IOS command exists to enable SNMP. The first snmp-server

global configuration command that you enter enables all versions of SNMP.

Command

Purpose

configure terminal

Enters global configuration mode.

no snmp-server

Disables the SNMP agent operation.

end

Returns to privileged EXEC mode.

Configuring Community Strings

Note: To disable access for an SNMP community, set the community string for that community to the null string (do not

enter a value for the community string).

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Configuring SNMP

How to Configure SNMP

Command

Purpose

configure terminal

Enters global configuration mode.

snmp-server community string

Configures the community string.

[view view-name] [ro | rw]

[access-list-number]

Note: The @ symbol is used for delimiting the context information. Avoid

using the @ symbol as part of the SNMP community string when

configuring this command.

string—Specifies a string that acts like a password and permits access

to the SNMP protocol. You can configure one or more community

strings of any length.

(Optional) view—Specifies the view record accessible to the

community.

(Optional) Specifies either read-only (ro) if you want authorized

management stations to retrieve MIB objects, or specifies read-write

(rw) if you want authorized management stations to retrieve and

modify MIB objects. By default, the community string permits

read-only access to all objects.

(Optional) access-list-number—Specifies an IP standard access list

numbered from 1 to 99 and 1300 to 1999.

access-list access-list-number

(Optional) If you specified an IP standard access list number in Step 2,

{deny | permit} source

then create the list, repeating the command as many times as necessary.

[source-wildcard]

access-list-number—Specifies the access list number specified in

Step 2.

deny — Denies access if the conditions are matched. The permit

keyword permits access if the conditions are matched.

source—Specifies the IP address of the SNMP managers that are

permitted to use the community string to gain access to the agent.

(Optional) source-wildcard—Specifies the wildcard bits in dotted

decimal notation to be applied to the source. Place ones in the bit

positions that you want to ignore.

The access list is always terminated by an implicit deny statement for

everything.

end

Returns to privileged EXEC mode.

Configuring SNMP Groups and Users

You can specify an identification name (engine ID) for the local or remote SNMP server engine on the switch. You can

configure an SNMP server group that maps SNMP users to SNMP views, and you can add new users to the SNMP group.

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Configuring SNMP

How to Configure SNMP

Command

Purpose

configure terminal

Enters global configuration mode.

snmp-server engineID {local engineid-string

Configures a name for either the local or remote copy of SNMP.

| remote ip-address [udp-port port-number]

engineid-string}

The engineid-string is a 24-character ID string with the name

of the copy of SNMP. You need not specify the entire

24-character engine ID if it has trailing zeros. Specify only the

portion of the engine ID up to the point where only zeros

remain in the value. For example, to configure an engine ID of

123400000000000000000000, you can enter this:

snmp-server engineID local 1234

If you select remote, specify the ip-address of the device that

contains the remote copy of SNMP and the optional User

Datagram Protocol (UDP) port on the remote device. The

default is 162.

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Configuring SNMP

How to Configure SNMP

Command

Purpose

snmp-server group groupname {v1 | v2c | v3

Configures a new SNMP group on the remote device.

{auth | noauth | priv}} [read readview] [write

writeview] [notify notifyview] [access

groupname—Specifies the name of the group.

access-list]

Specify a security model:

— v1 is the least secure of the possible security models.

— v2c is the second least secure model. It allows

transmission of informs and integers twice the normal

width.

— v3, the most secure, requires you to select an

authentication level:

auth—Enables the Message Digest 5 (MD5) and the Secure

Hash Algorithm (SHA) packet authentication.

noauth—Enables the noAuthNoPriv security level. This is

the default if no keyword is specified.

priv—Enables Data Encryption Standard (DES) packet

encryption (also called privacy).

Note: The priv keyword is available only when the cryptographic

software image is installed.

(Optional) read readview—Specifies a string (not to exceed 64

characters) that is the name of the view in which you can only

view the contents of the agent.

(Optional) write writeview—Specifies a string (not to exceed

64 characters) that is the name of the view in which you enter

data and configure the contents of the agent.

(Optional) notify notifyview—Specifies a string (not to exceed

64 characters) that is the name of the view in which you

specify a notify, inform, or trap.

(Optional) access access-list—Specifies a string (not to

exceed 64 characters) that is the name of the access list.

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Configuring SNMP

How to Configure SNMP

Command

Purpose

snmp-server user username groupname

Adds a new user for an SNMP group.

{remote host [udp-port port]} {v1 [access

access-list] | v2c [access access-list] | v3

username—Specifies a name of the user on the host that

[encrypted] [access access-list] [auth {md5

connects to the agent.

| sha} auth-password]} [priv {des | 3des | aes

groupname—Specifies a name of the group to which the user

{128 | 192 | 256}} priv-password]

is associated.

remote—Specifies a remote SNMP entity to which the user

belongs and the hostname or IP address of that entity with the

optional UDP port number. The default is 162.

Enters the SNMP version number (v1, v2c, or v3). If you enter

v3, you have these additional options:

— encrypted—Specifies that the password appears in

encrypted format. This keyword is available only when the

v3 keyword is specified.

— auth—Specifies an authentication level setting session

that can be either the HMAC-MD5-96 (md5) or the

HMAC-SHA-96 (sha) authentication level and requires a

password string auth-password (not to exceed 64

characters).

If you enter v3 and the switch is running the cryptographic

software image, you can also configure a private (priv)

encryption algorithm and password string priv-password (not

to exceed 64 characters).

— priv—Specifies the User-based Security Model (USM).

— des—Specifies the use of the 56-bit DES algorithm.

—

3des—Specifies the use of the 168-bit DES algorithm.

— aes—Specifies the use of the DES algorithm. You must

select either 128-bit, 192-bit, or 256-bit encryption.

(Optional) Enters access access-list with a string (not to

exceed 64 characters) that is the name of the access list.

end

Returns to privileged EXEC mode.

Configuring SNMP Notifications

Command

Purpose

configure terminal

Enters global configuration mode.

snmp-server engineID remote

Specifies the engine ID for the remote host.

ip-address engineid-string

snmp-server user username

Configures an SNMP user to be associated with the remote host created

groupname {remote host [udp-port

in Step 2.

port]} {v1 [access access-list] | v2c

[access access-list] | v3 [encrypted]

Note: You cannot configure a remote user for an address without first

[access access-list] [auth {md5 | sha}

configuring the engine ID for the remote host. Otherwise, you receive an

auth-password]}

error message, and the command is not executed.

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Configuring SNMP

How to Configure SNMP

Command

Purpose

snmp-server group groupname {v1 |

Configures an SNMP group.

v2c | v3 {auth | noauth | priv}} [read

readview] [write writeview] [notify

notifyview] [access access-list]

snmp-server host host-addr

Specifies the recipient of an SNMP trap operation.

[informs | traps] [version {1 | 2c | 3

{auth | noauth | priv}}]

host-addr—Specifies the name or Internet address of the host (the

community-string [notification-type]

targeted recipient).

(Optional) informs—Specifies SNMP informs to be sent to the host.

(Optional) traps (the default)—Specifies SNMP traps to be sent to the

host.

(Optional) Specifies the SNMP version (1, 2c, or 3). SNMPv1 does

not support informs.

(Optional) Version 3—Selects authentication level auth, noauth, or

priv.

Note: The priv keyword is available only when the cryptographic

software image is installed.

community-string—When version 1 or version 2c is specified, enters

the password-like community string sent with the notification

operation. When version 3 is specified, enter the SNMPv3

username.

Note: The @ symbol is used for delimiting the context information. Avoid

using the @ symbol as part of the SNMP community string when

configuring this command.

(Optional) notification-type—Specifies a notification type. Use the

keywords listed in Table 55 on page 562. If no type is specified, all

notifications are sent.

snmp-server enable traps

Enables the switch to send traps or informs and specifies the type of

notification-types

notifications to be sent. For a list of notification types, see Table 55 on

page 562, or enter snmp-server enable traps ?

To enable multiple types of traps, you must enter a separate

snmp-server enable traps command for each trap type.

Note: When you configure a trap by using the notification type

port-security, configure the port security trap first, and then configure

the port security trap rate:

snmp-server enable traps port-security

snmp-server enable traps port-security trap-rate rate

snmp-server trap-source interface-id

(Optional) Specifies the source interface, which provides the IP address

for the trap message. This command also sets the source IP address for

informs.

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Configuring SNMP

How to Configure SNMP

Command

Purpose

snmp-server queue-length length

(Optional) Establishes the message queue length for each trap host. The

range is 1 to 1000; the default is 10.

snmp-server trap-timeout seconds

(Optional) Defines how often to resend trap messages. The range is 1 to

1000; the default is 30 seconds.

10.

end

Returns to privileged EXEC mode.

Setting the CPU Threshold Notification Types and Values

Command

Purpose

configure terminal

Enters global configuration mode.

process cpu threshold type {total |

Sets the CPU threshold notification types and values:

process | interrupt} rising percentage

total—Sets the notification type to total CPU utilization.

interval seconds [falling fall-percentage

interval seconds]

process—Sets the notification type to CPU process utilization.

interrupt—Sets the notification type to CPU interrupt utilization.

rising percentage—Specifies the percentage (1 to 100) of CPU

resources that, when exceeded for the configured interval, sends

a CPU threshold notification.

interval seconds—Specifies the duration of the CPU threshold

violation in seconds (5 to 86400) that, when met, sends a CPU

threshold notification.

falling fall-percentage—Specifies the percentage (1 to 100) of

CPU resources that, when usage falls below this level for the

configured interval, sends a CPU threshold notification.

This value must be equal to or less than the rising percentage

value. If not specified, the falling fall-percentage value is the

same as the rising percentage value.

end

Returns to privileged EXEC mode.

Setting the Agent Contact and Location Information

Command

Purpose

configure terminal

Enters global configuration mode.

snmp-server contact text

Sets the system contact string.

snmp-server location text

Sets the system location string.

end

Returns to privileged EXEC mode.

570

Configuring SNMP

Monitoring and Maintaining SNMP

Limiting TFTP Servers Used Through SNMP

Command

Purpose

configure terminal

Enters global configuration mode.

snmp-server tftp-server-list

Limits TFTP servers used for configuration file copies through

access-list-number

SNMP to the servers in the access list.

access-list-number—Enters an IP standard access list numbered

from 1 to 99 and 1300 to 1999.

access-list access-list-number {deny |

Creates a standard access list, repeating the command as many

permit} source [source-wildcard]

times as necessary.

access-list-number—Enters the access list number specified in

Step 2.

deny—Denies access if the conditions are matched. The

permit keyword permits access if the conditions are matched.

source—Enters the IP address of the TFTP servers that can

access the switch.

(Optional) source-wildcard—Enters the wildcard bits, in dotted

decimal notation, to be applied to the source. Place ones in the

bit positions that you want to ignore.

Recall that the access list is always terminated by an implicit deny

statement for everything.

end

Returns to privileged EXEC mode.

Monitoring and Maintaining SNMP

Command

Purpose

show snmp

Displays SNMP statistics.

show snmp engineID [local | remote]

Displays information on the local SNMP engine and all remote engines

that have been configured on the device.

show snmp group

Displays information on each SNMP group on the network.

show snmp pending

Displays information on pending SNMP requests.

show snmp sessions

Displays information on the current SNMP sessions.

show snmp user

Displays information on each SNMP user name in the SNMP users table.

Note: You must use this command to display SNMPv3 configuration

information for auth | noauth | priv mode. This information is not

displayed in the show running-config output.

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Configuring SNMP

Configuration Examples for SNMP

Enabling SNMP Versions: Example

This example shows how to enable all versions of SNMP. The configuration permits any SNMP manager to access all

objects with read-only permissions using the community string public. This configuration does not cause the switch to

send any traps.

Switch(config)# snmp-server community public

Permit SNMP Manager Access: Example

This example shows how to permit any SNMP manager to access all objects with read-only permission using the

community string public. The switch also sends VTP traps to the hosts 192.180.1.111 and 192.180.1.33 using SNMPv1

and to the host 192.180.1.27 using SNMPv2C. The community string public is sent with the traps.

Switch(config)# snmp-server community public

Switch(config)# snmp-server enable traps vtp

Switch(config)# snmp-server host 192.180.1.27 version 2c public

Switch(config)# snmp-server host 192.180.1.111 version 1 public

Switch(config)# snmp-server host 192.180.1.33 public

Allow Read-Only Access: Example

This example shows how to allow read-only access for all objects to members of access list 4 that use the comaccess

community string. No other SNMP managers have access to any objects. SNMP Authentication Failure traps are sent by

SNMPv2C to the host cisco.com using the community string public.

Switch(config)# snmp-server community comaccess ro 4

Switch(config)# snmp-server enable traps snmp authentication

Switch(config)# snmp-server host cisco.com version 2c public

Configure SNMP Traps: Examples

This example shows how to send entity MIB traps to the host cisco.com. The community string is restricted. The first line

enables the switch to send entity MIB traps in addition to any traps previously enabled. The second line specifies the

destination of these traps and overwrites any previous snmp-server host commands for the host cisco.com.

Switch(config)# snmp-server enable traps entity

Switch(config)# snmp-server host cisco.com restricted entity

This example shows how to enable the switch to send all traps to the host myhost.cisco.com using the community string

public:

Switch(config)# snmp-server enable traps

Switch(config)# snmp-server host myhost.cisco.com public

Associating a User with a Remote Host: Example

This example shows how to associate a user with a remote host and to send auth (authNoPriv) authentication-level

informs when the user enters global configuration mode:

Switch(config)# snmp-server engineID remote 192.180.1.27 00000063000100a1c0b4011b

Switch(config)# snmp-server group authgroup v3 auth

Switch(config)# snmp-server user authuser authgroup remote 192.180.1.27 v3 auth md5 mypassword

Switch(config)# snmp-server user authuser authgroup v3 auth md5 mypassword

Switch(config)# snmp-server host 192.180.1.27 informs version 3 auth authuser config

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Configuring SNMP

Additional References

Cisco Industrial Ethernet 4000, 4010 and 5000 Switch Software. Configuration Guide (2022) - page 21