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Catalyst 3750-X and 3560-X Switch Software Configuration Guide
OL-21521-01
Chapter 34 Configuring System Message Logging
Configuring System Message Logging
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 stack master. 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.
Configuring System Message Logging
• System Log Message Format, page 34-2
• Default System Message Logging Configuration, page 34-4
• Disabling Message Logging, page 34-4 (optional)
• Setting the Message Display Destination Device, page 34-5 (optional)
• Synchronizing Log Messages, page 34-6 (optional)
• Enabling and Disabling Time Stamps on Log Messages, page 34-8 (optional)
• Enabling and Disabling Sequence Numbers in Log Messages, page 34-8 (optional)
• Defining the Message Severity Level, page 34-9 (optional)
• Limiting Syslog Messages Sent to the History Table and to SNMP, page 34-10 (optional)
• Enabling the Configuration-Change Logger, page 34-11 (optional)
• Configuring UNIX Syslog Servers, page 34-12 (optional)

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:
For Catalyst 3750-X switches, seq no:timestamp: %facility-severity-MNEMONIC:description
(hostname-n)
For Catalyst 3560-X switches, 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.