- Preface
- Using the Command-Line Interface
- Using the Web Graphical User Interface
- Administering the System
- Performing Switch Setup Configuration
- Configuring Right-To-Use Licenses
- Configuring Administrator Usernames and Passwords
- Configuring 802.11 parameters and Band Selection
- Configuring Client Roaming
- Configuring Application Visibility and Control
- Configuring Voice and Video Parameters
- Configuring RFID Tag Tracking
- Configuring Location Settings
- Monitoring Flow Control
- Configuring SDM Templates
- Configuring System Message Logs
- Configuring Online Diagnostics
- Managing Configuration Files
- Configuration Replace and Configuration Rollback
- Working with the Flash File System
- Working with Cisco IOS XE Software Bundles
- Troubleshooting the Software Configuration
- Index
- Finding Feature Information
- Information About Configuring System Message Logs
- How to Configure System Message Logs
- Setting the Message Display Destination Device
- Synchronizing Log Messages
- Disabling Message Logging
- Enabling and Disabling Time Stamps on Log Messages
- Enabling and Disabling Sequence Numbers in Log Messages
- Defining the Message Severity Level
- Limiting Syslog Messages Sent to the History Table and to SNMP
- Logging Messages to a UNIX Syslog Daemon
- Monitoring and Maintaining System Message Logs
- Configuration Examples for System Message Logs
- Additional References for System Message Logs
- Feature History and Information For System Message Logs
Configuring System Message Logs
- Finding Feature Information
- Information About Configuring System Message Logs
- How to Configure System Message Logs
- Monitoring and Maintaining System Message Logs
- Configuration Examples for System Message Logs
- Additional References for System Message Logs
- Feature History and Information For System Message Logs
Finding Feature Information
Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table at the end of this module.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
Information About Configuring System Message Logs
- System Messsage Logging
- System Log Message Format
- Default System Message Logging Settings
- Syslog Message Limits
System Messsage Logging
By default, a switch sends the output from system messages and debug privileged EXEC commands to a logging process. Stack members can trigger system messages. A stack member that generates a system message appends its hostname in the form of hostname-n, where n is a switch range from 1 to 4, and redirects the output to the logging process on the active switch. Though the active switch is a stack member, it does not append its hostname to system messages. The logging process controls the distribution of logging messages to various destinations, such as the logging buffer, terminal lines, or a UNIX syslog server, depending on your configuration. The process also sends messages to the console.
When the logging process is disabled, messages are sent only to the console. The messages are sent as they are generated, so message and debug output are interspersed with prompts or output from other commands. Messages appear on the active consoles after the process that generated them has finished.
You can set the severity level of the messages to control the type of messages displayed on the consoles and each of the destinations. You can time-stamp log messages or set the syslog source address to enhance real-time debugging and management. For information on possible messages, see the system message guide for this release.
You can access logged system messages by using the switch command-line interface (CLI) or by saving them to a properly configured syslog server. The switch software saves syslog messages in an internal buffer on a standalone switch, and in the case of a switch stack, on the active switch. If a standalone switch or the stack master fails, the log is lost unless you had saved it to flash memory.
You can remotely monitor system messages by viewing the logs on a syslog server or by accessing the switch through Telnet, through the console port, or through the Ethernet management port. In a switch stack, all stack member consoles provide the same console output.
Note | The syslog format is compatible with 4.3 BSD UNIX. |
System Log Message Format
System log messages can contain up to 80 characters and a percent sign (%), which follows the optional sequence number or time-stamp information, if configured. Depending on the switch, messages appear in one of these formats:
-
seq no:timestamp: %facility-severity-MNEMONIC:description (hostname-n)
-
seq no:timestamp: %facility-severity-MNEMONIC:description
Element |
Description |
---|---|
seq no: |
Stamps log messages with a sequence number only if the service sequence-numbers global configuration command is configured. |
timestamp formats: mm/dd h h:mm:ss or hh:mm:ss (short uptime) or d h (long uptime) |
Date and time of the message or event. This information appears only if the service timestamps log [datetime | log] global configuration command is configured. |
facility |
The facility to which the message refers (for example, SNMP, SYS, and so forth). |
severity |
Single-digit code from 0 to 7 that is the severity of the message. |
MNEMONIC |
Text string that uniquely describes the message. |
description |
Text string containing detailed information about the event being reported. |
hostname-n |
Hostname of a stack member and its switch number in the stack. Though the active switch is a stack member, it does not append its hostname to system messages. |
Default System Message Logging Settings
Feature |
Default Setting |
---|---|
System message logging to the console |
Enabled. |
Console severity |
Debugging. |
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. |
Server facility |
Local7 |
Server severity |
Informational. |
Syslog Message Limits
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.
The history table lists the level keywords and severity level. For SNMP usage, the severity level values increase by 1. For example, emergencies equal 1, not 0, and critical equals 3, not 2.
How to Configure System Message Logs
- Setting the Message Display Destination Device
- Synchronizing Log Messages
- Disabling Message Logging
- Enabling and Disabling Time Stamps on Log Messages
- Enabling and Disabling Sequence Numbers in Log Messages
- Defining the Message Severity Level
- Limiting Syslog Messages Sent to the History Table and to SNMP
- Logging Messages to a UNIX Syslog Daemon
Setting the Message Display Destination Device
If message logging is enabled, you can send messages to specific locations in addition to the console.
This task is optional.
1.
configure terminal
2.
logging buffered [size]
3.
logging
host
4.
logging file flash:
filename [max-file-size [min-file-size]]
[severity-level-number | type]
5.
end
6.
terminal
monitor
DETAILED STEPS
Synchronizing Log Messages
You can synchronize unsolicited messages and debug privileged EXEC command output with solicited device output and prompts for a specific console port line or virtual terminal line. You can identify the types of messages to be output asynchronously based on the level of severity. You can also configure the maximum number of buffers for storing asynchronous messages for the terminal after which messages are dropped.
When synchronous logging of unsolicited messages and debug command output is enabled, unsolicited device output appears on the console or printed after solicited device output appears or is printed. Unsolicited messages and debug command output appears on the console after the prompt for user input is returned. Therefore, unsolicited messages and debug command output are not interspersed with solicited device output and prompts. After the unsolicited messages appear, the console again displays the user prompt.
This task is optional.
1.
configure terminal
2.
line [console | vty] line-number
[ending-line-number]
3.
logging synchronous [level [severity-level
| all] | limit
number-of-buffers]
4.
end
DETAILED STEPS
Command or Action | Purpose | |
---|---|---|
Step 1 | configure terminal Example:
SwitchControllerDevice# configure terminal
|
Enters global configuration mode. |
Step 2 | line [console | vty] line-number
[ending-line-number] Example:
SwitchControllerDevice(config)# line console
|
Specifies the line to be configured for synchronous logging of messages.
You can change the setting of all 16 vty lines at once by entering: line vty 0 15 You can also 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. |
Step 3 | logging synchronous [level [severity-level
| all] | limit
number-of-buffers] Example:
SwitchControllerDevice(config)# logging synchronous level 3 limit 1000
|
Enables synchronous logging of messages.
|
Step 4 | end Example:
SwitchControllerDevice(config)# end
|
Returns to privileged EXEC mode. |
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.
The logging synchronous global configuration command also affects the display of messages to the console. When this command is enabled, messages appear only after you press Return.
To reenable message logging after it has been disabled, use the logging on global configuration command.
This task is optional.
1.
configure terminal
2.
no logging console
3.
end
DETAILED STEPS
Command or Action | Purpose | |
---|---|---|
Step 1 | configure terminal Example:
SwitchControllerDevice# configure terminal
|
Enters global configuration mode. |
Step 2 | no logging console Example:
SwitchControllerDevice(config)# no logging console
|
Disables message logging. |
Step 3 | end Example:
SwitchControllerDevice(config)# end
|
Returns to privileged EXEC mode. |
Enabling and Disabling Time Stamps on Log Messages
By default, log messages are not time-stamped.
This task is optional.
1.
configure terminal
2.
Use one of these commands:
3.
end
DETAILED STEPS
Command or Action | Purpose | |
---|---|---|
Step 1 | configure terminal Example:
SwitchControllerDevice# configure terminal
|
Enters global configuration mode. |
Step 2 | Use one of these commands:
Example: SwitchControllerDevice(config)# service timestamps log uptime
or SwitchControllerDevice(config)# service timestamps log datetime
|
Enables log time stamps. |
Step 3 | end Example:
SwitchControllerDevice(config)# end
|
Returns to privileged EXEC mode. |
Enabling and Disabling Sequence Numbers in Log Messages
If there is more than one log message with the same time stamp, you can display messages with sequence numbers to view these messages. By default, sequence numbers in log messages are not displayed.
This task is optional.
1.
configure terminal
2.
service sequence-numbers
3.
end
DETAILED STEPS
Command or Action | Purpose | |
---|---|---|
Step 1 | configure terminal Example:
SwitchControllerDevice# configure terminal
|
Enters global configuration mode. |
Step 2 | service sequence-numbers Example:
SwitchControllerDevice(config)# service sequence-numbers
|
Enables sequence numbers. |
Step 3 | end Example:
SwitchControllerDevice(config)# end
|
Returns to privileged EXEC mode. |
Defining the Message Severity Level
Limit messages displayed to the selected device by specifying the severity level of the message.
This task is optional.
1.
configure terminal
2.
logging console
level
3.
logging monitor
level
4.
logging trap
level
5.
end
DETAILED STEPS
Command or Action | Purpose | |
---|---|---|
Step 1 | configure terminal Example:
SwitchControllerDevice# configure terminal
|
Enters global configuration mode. |
Step 2 | logging console
level Example:
SwitchControllerDevice(config)# logging console 3
|
Limits messages logged to the console. By default, the console receives debugging messages and numerically lower levels. |
Step 3 | logging monitor
level Example:
SwitchControllerDevice(config)# logging monitor 3
|
Limits messages logged to the terminal lines. By default, the terminal receives debugging messages and numerically lower levels. |
Step 4 | logging trap
level Example:
SwitchControllerDevice(config)# logging trap 3
|
Limits messages logged to the syslog servers. By default, syslog servers receive informational messages and numerically lower levels. |
Step 5 | end Example:
SwitchControllerDevice(config)# end
|
Returns to privileged EXEC mode. |
Limiting Syslog Messages Sent to the History Table and to SNMP
This task explains how to limit syslog messages that are sent to the history table and to SNMP.
This task is optional.
1.
configure terminal
2.
logging history
level
3.
logging history size
number
4.
end
DETAILED STEPS
Command or Action | Purpose | |
---|---|---|
Step 1 | configure terminal Example:
SwitchControllerDevice# configure terminal
|
Enters global configuration mode. |
Step 2 | logging history
level Example:
SwitchControllerDevice(config)# logging history 3
|
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. |
Step 3 | logging history size
number Example:
SwitchControllerDevice(config)# logging history size 200
|
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. |
Step 4 | end Example:
SwitchControllerDevice(config)# end
|
Returns to privileged EXEC mode. |
Logging Messages to a UNIX Syslog Daemon
This task 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 to the file /etc/syslog.conf.
2. Enter these commands at the UNIX shell prompt.
3. Make sure the syslog daemon reads the new changes.
DETAILED STEPS
Command or Action | Purpose | |
---|---|---|
Step 1 |
Add a line to the file /etc/syslog.conf. Example:
local7.debug /usr/adm/logs/cisco.log
| |
Step 2 | Enter these commands at the UNIX shell prompt. Example: $ touch /var/log/cisco.log $ chmod 666 /var/log/cisco.log | Creates the log file. The syslog daemon sends messages at this level or at a more severe level to this file. |
Step 3 | Make sure the syslog daemon reads the new changes. Example: $ kill -HUP `cat /etc/syslog.pid` |
For more information, see the man syslog.conf and man syslogd commands on your UNIX system. |
Monitoring and Maintaining System Message Logs
Monitoring Configuration Archive Logs
Command |
Purpose |
---|---|
show archive log config {all | number [end-number] | user username [session number] number [end-number] | statistics} [provisioning] |
Displays the entire configuration log or the log for specified parameters. |
Configuration Examples for System Message Logs
Example: Stacking System Message
This example shows a partial switch system message for active switch and a stack member (hostname Switch-2):
00:00:46: %LINK-3-UPDOWN: Interface Port-channel1, changed state to up 00:00:47: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/1, changed state to up 00:00:47: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/2, changed state to up 00:00:48: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to down 00:00:48: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/1, changed state to down 2 *Mar 1 18:46:11: %SYS-5-CONFIG_I: Configured from console by vty2 (10.34.195.36) 18:47:02: %SYS-5-CONFIG_I: Configured from console by vty2 (10.34.195.36) *Mar 1 18:48:50.483 UTC: %SYS-5-CONFIG_I: Configured from console by vty2 (10.34.195.36) 00:00:46: %LINK-3-UPDOWN: Interface Port-channel1, changed state to up (Switch-2) 00:00:47: %LINK-3-UPDOWN: Interface GigabitEthernet2/0/1, changed state to up (Switch-2) 00:00:47: %LINK-3-UPDOWN: Interface GigabitEthernet2/0/2, changed state to up (Switch-2) 00:00:48: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to down (Switch-2) 00:00:48: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet2/0/1, changed state to down 2 (Switch-2)
Example: Switch System Message
This example shows a partial switch system message on a switch:
00:00:46: %LINK-3-UPDOWN: Interface Port-channel1, changed state to up 00:00:47: %LINK-3-UPDOWN: Interface GigabitEthernet0/1, changed state to up 00:00:47: %LINK-3-UPDOWN: Interface GigabitEthernet0/2, changed state to up 00:00:48: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to down 00:00:48: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/1, changed state to down 2 *Mar 1 18:46:11: %SYS-5-CONFIG_I: Configured from console by vty2 (10.34.195.36) 18:47:02: %SYS-5-CONFIG_I: Configured from console by vty2 (10.34.195.36) *Mar 1 18:48:50.483 UTC: %SYS-5-CONFIG_I: Configured from console by vty2 (10.34.195.36)
Additional References for System Message Logs
Related Documents
Related Topic | Document Title |
---|---|
System management commands |
System Management Command Reference (Catalyst 3850 Switches) |
Platform-independent command references | Configuration Fundamentals Command Reference, Cisco IOS XE Release 3S (Catalyst 3850 Switches) |
Platform-independent configuration information | Configuration Fundamentals Configuration Guide, Cisco IOS XE Release 3S (Catalyst 3850 Switches) IP Addressing Configuration Guide Library, Cisco IOS XE Release 3S (Catalyst 3850 Switches) |
Standards and RFCs
Standard/RFC | Title |
---|---|
None | — |
MIBs
MIB | MIBs Link |
---|---|
All supported MIBs for this release. |
To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL: |
Technical Assistance
Description | Link |
---|---|
The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies. To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds. Access to most tools on the Cisco Support website requires a Cisco.com user ID and password. |
Feature History and Information For System Message Logs
Release |
Modification |
---|---|
Cisco IOS XE 3.2SE |
This feature was introduced. |