- Overview
- Assigning the Switch IP Address and Default Gateway
- Configuring Switch Boot Optimization
- Administering the Switch
- Configuring the Switch Alarms
- Configuring SDM Templates
- Configuring Smartports Macros
- Configuring LLDP and LLDP-MED
- Configuring Port-Based Traffic Control
- Configuring CDP
- Configuring SPAN and RSPAN
- Configuring RMON
- Configuring System Message Logging
- Configuring SNMP
- Configuring Embedded Event Manager
- Configuring Cisco IOS IP SLAs Operations
- Configuring Ethernet OAM, CFM, and E-LMI
- Configuring Online Diagnostics
- Supported MIBs
- Information About System Message Logging
- Prerequisites
- Guidelines and Limitations
- Default Settings
- Configuring System Message Logging
- Disabling Message Logging
- Setting the Message Display Destination Device
- Synchronizing Log Messages
- 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
- Enabling the Configuration-Change Logger
- Configuring UNIX Syslog Servers
Configuring System Message Logging
This chapter describes how to configure system message logging on the Cisco Industrial Ethernet 2000U Series (IE 2000U) and Connected Grid Switches, hereafter referred to as switch .
Note
For complete syntax and usage information for the commands used in this chapter, see the documents listed in the“Related Documents” section.
Information About System Message Logging
By default, a switch sends the output from system messages and debug privileged EXEC commands to a logging process. 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.
NoteThe syslog format is compatible with 4.3 BSD UNIX.
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 console 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, Cisco System Messages .
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.
You can remotely monitor system messages by viewing the logs on a syslog server or by accessing the switch through Telnet or through the console port.
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. Messages appear in this format:
seq no:timestamp: %facility-severity-MNEMONIC:description
The part of the message preceding the percent sign depends on the setting of the service sequence-numbers , service timestamps log datetime , service timestamps log datetime [ localtime ] [ msec ] [ show-timezone ] , or service timestamps log uptime global configuration command.
Table 13-1 describes the elements of syslog messages.
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Stamps log messages with a sequence number only if the service sequence-numbers global configuration command is configured. For more information, see the “Enabling and Disabling Sequence Numbers in Log Messages” section. |
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| mm/dd h h:mm:ss |
Date and time of the message or event. This information appears only if the service timestamps log [ datetime | log ] global configuration command is configured. For more information, see the “Enabling and Disabling Time Stamps on Log Messages” section. |
The facility to which the message refers (for example, SNMP, SYS, and so forth). For a list of supported facilities, see Table 13-3. |
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Single-digit code from 0 to 7 that is the severity of the message. For a description of the severity levels, see Table 13-2. |
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Text string containing detailed information about the event being reported. |
This example shows a partial switch system message:
Prerequisites
Review the “Information About System Message Logging” section.
Guidelines and Limitations
Default Settings
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Debugging (and numerically lower levels; see Table 13-2). |
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Local7 (see Table 13-3). |
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Informational (and numerically lower levels; see Table 13-2). |
Configuring System Message Logging
- Disabling Message Logging (optional)
- Setting the Message Display Destination Device (optional)
- Synchronizing Log Messages (optional)
- Enabling and Disabling Time Stamps on Log Messages (optional)
- Enabling and Disabling Sequence Numbers in Log Messages (optional)
- Defining the Message Severity Level (optional)
- Limiting Syslog Messages Sent to the History Table and to SNMP (optional)
- Enabling the Configuration-Change Logger (optional)
- Configuring UNIX Syslog Servers (optional)
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.
BEFORE YOU BEGIN
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 . For more information, see the “Synchronizing Log Messages” section.
DETAILED STEPS
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To re-enable message logging after it has been disabled, use the logging on global configuration command.
EXAMPLE
Setting the Message Display Destination Device
If message logging is enabled, you can send messages to specific locations in addition to the console.
The logging buffered global configuration command copies logging messages to an internal buffer. The buffer is circular, so newer messages overwrite older messages after the buffer is full. To display the messages that are logged in the buffer, use the show logging privileged EXEC command. The first message displayed is the oldest message in the buffer. To clear the contents of the buffer, use the clear logging privileged EXEC command.
BEFORE YOU BEGIN
If message logging is disabled, use the logging on global configuration command to re-enable it.
DETAILED STEPS
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Log messages to an internal buffer on the switch. The default buffer size is 4096. The range is 4096 to 2147483647 bytes. If the switch fails, the log file is lost unless you 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. |
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Log messages to a UNIX syslog server host. For host , specify 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. For complete syslog server configuration steps, see the “Configuring UNIX Syslog Servers” section. |
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logging file flash: filename [ max-file-size [ min-file-size ]] [ severity-level-number | type ] |
Store log messages in a file in flash memory.
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Log 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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To disable logging to the console, use the no logging console global configuration command. To disable logging to a file, use the no logging file [ severity-level-number | type ] global configuration command.
EXAMPLE
The following example shows how to enable standard system logging to the local syslog buffer:
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.
BEFORE YOU BEGIN
DETAILED STEPS
To disable synchronization of unsolicited messages and debug output, use the no logging synchronous [ level severity-level | all ] [ limit number-of-buffers ] line configuration command.
EXAMPLE
In the following example, synchronous logging for line 4 is enabled with a severity level of 6. Then synchronous logging for line 2 is enabled with a severity level of 7 and is specified with a maximum number of buffer lines of 1,000.
Enabling and Disabling Time Stamps on Log Messages
BEFORE YOU BEGIN
Ensure that the system clock is set correctly. For more information, see Chapter4, “Administering the Switch”
DETAILED STEPS
To disable time stamps for both debug and log messages, use the no service timestamps global configuration command.
EXAMPLE
This example shows part of a logging display with the service timestamps log datetime global configuration command enabled:
This example shows part of a logging display with the s ervice timestamps log uptime global configuration command enabled:
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.
BEFORE YOU BEGIN
Review the “Information About System Message Logging” section.
DETAILED STEPS
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To disable sequence numbers, use the no service sequence-numbers global configuration command.
EXAMPLE
This example shows part of a logging display with sequence numbers enabled:
Defining the Message Severity Level
You can limit messages displayed to the selected device by specifying the severity level of the message. Table 13-2 describes the level keywords. It also lists the corresponding UNIX syslog definitions from the most severe level to the least severe level.
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The software generates four other 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. For information on how to recover from these malfunctions, see the system message guide for this release.
- 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.
BEFORE YOU BEGIN
DETAILED STEPS
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Limit messages logged to the console. By default, the console receives debugging messages and numerically lower levels (see Table 13-2). |
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Limit messages logged to the terminal lines. By default, the terminal receives debugging messages and numerically lower levels (see Table 13-2). |
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Limit messages logged to the syslog servers. By default, syslog servers receive informational messages and numerically lower levels (see Table 13-2). For complete syslog server configuration steps, see the “Configuring UNIX Syslog Servers” section. |
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NoteSpecifying alevel causes messages at that level and numerically lower levels to appear at the destination.
To disable logging to the console, use the no logging console global configuration command. To disable logging to a terminal other than the console, use the no logging monitor global configuration command. To disable logging to syslog servers, use the no logging trap global configuration command.
EXAMPLE
The following example shows how to change the level of messages sent to the console terminal to alerts, meaning that messages at levels 0 and 1 are sent:
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 (see Table 13-2) are stored in the history table even if syslog traps are not enabled.
BEFORE YOU BEGIN
For information about enabling syslog message traps using the snmp-server enable trap command, see Chapter14, “Configuring SNMP”
DETAILED STEPS
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logging history level1 |
Change the default level of syslog messages stored in the history file and sent to the SNMP server. See Table 13-2 for a list of level keywords. By default, warnings , errors , critical , alerts , and emergencies messages are sent. |
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Specify 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. |
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1.Table 13-2 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. |
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.
To return the logging of syslog messages to the default level, use the no logging history global configuration command. To return the number of messages in the history table to the default value, use the no logging history size global configuration command.
EXAMPLE
In the following example, the logging history 1 command is used to configure the system to save only level 1 (alert) and level 0 (emergency) messages to the logging history table, and, by extension, to send only these levels in the SNMP notifications. The configuration is then confirmed using the show logging history command.
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). You can clear the log at any time by entering the no logging enable command followed by the logging enable command to disable and reenable logging.
Use the show archive log config { all | number [ end-number ] | user username [ session number ] number [ end-number ] | statistics } [ provisioning ] privileged EXEC command to display the complete configuration log or the log for specified parameters.
BEFORE YOU BEGIN
If you disable configuration logging, all configuration log records that were collected are purged.
DETAILED STEPS
EXAMPLE
This example shows how to enable the configuration-change logger and to set the number of entries in the log to 500:
This is an example of output for the configuration log:
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.
BEFORE YOU BEGIN
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.
DETAILED STEPS
Step 2 Add a line such as the following to the file /etc/syslog.conf:
The local7 keyword specifies the logging facility to be used; see Table 13-3 for information on the facilities. The debug keyword specifies the syslog level; see Table 13-2 for information on the severity levels. 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.
Step 3 Create the log file by entering these commands at the UNIX shell prompt:
Step 4 Make sure the syslog daemon reads the new changes:
For more information, see the man syslog.conf and man syslogd commands on your UNIX system.
Configuring the UNIX System Logging Facility
When sending system log messages to an external device, you can cause the switch to identify its messages as originating from any of the UNIX syslog facilities.
Table 13-3 lists the UNIX system facilities supported by the software.
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BEFORE YOU BEGIN
For more information about the UNIX system facilities, consult the operator’s manual for your UNIX operating system.
DETAILED STEPS
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Log messages to a UNIX syslog server host by entering its IP address. To build a list of syslog servers that receive logging messages, enter this command more than once. |
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Limit messages logged to the syslog servers. Be default, syslog servers receive informational messages and lower. See Table 13-2 for level keywords. |
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Configure the syslog facility. See Table 13-3 for facility-type keywords. |
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To remove a syslog server, use the no logging host global configuration command, and specify the syslog server IP address. To disable logging to syslog servers, enter the no logging trap global configuration command.
EXAMPLE
In the following example, the user configures the syslog facility to the kernel facility type:
Verifying the Configuration
To display the logging configuration and the contents of the log buffer, use the show logging privileged EXEC command. For information about the fields in this display, see the Cisco IOS Configuration Fundamentals Command Reference, Release 15.2M&T .
Configuration Example
The following example shows how to enable standard system logging to the local syslog buffer:
In the following example, synchronous logging for line 4 is enabled with a severity level of 6. Then synchronous logging for line 2 is enabled with a severity level of 7 and is specified with a maximum number of buffer lines of 1,000.
This example shows part of a logging display with the service timestamps log datetime global configuration command enabled:
This example shows part of a logging display with the s ervice timestamps log uptime global configuration command enabled:
This example shows part of a logging display with sequence numbers enabled:
The following example shows how to change the level of messages sent to the console terminal to alerts, meaning that messages at levels 0 and 1 are sent:
This example shows how to enable the configuration-change logger and to set the number of entries in the log to 500:
In the following example, the logging history 1 command is used to configure the system to save only level 1 (alert) and level 0 (emergency) messages to the logging history table, and, by extension, to send only these levels in the SNMP notifications. The configuration is then confirmed using the show logging history command.
This is an example of output for the configuration log:
Related Documents
Feature History
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