To specify the length of time that logs are maintained in the logging archive, use the archive-length command in logging archive configuration mode. To return to the default, use the no form of this command.

Command Default

weeks: 4 weeks

Command Modes

Logging archive configuration

Usage Guidelines

Use the archive-length command to specify the maximum number of weeks that the archive logs are maintained in the archive. Any logs older than this number are automatically removed from the archive.

To specify the amount of space allotted for syslogs on a device, use the archive-size command in logging archive configuration mode. To return to the default, use the no form of this command.

Command Default

size: 20 MB

Command Modes

Logging archive configuration

Usage Guidelines

Use the archive-length command to specify the maximum total size of the syslog archives on a storage device. If the size is exceeded, then the oldest file in the archive is deleted to make space for new logs.

To clear system logging (syslog) messages from the logging buffer, use the clear logging command in EXEC mode.

Syntax Description

This command has no keywords or arguments.

Command Default

None

Command Modes

EXEC

Usage Guidelines

Use the clear logging command to empty the contents of the logging buffer. When the logging buffer becomes full, new logged messages overwrite old messages.

Use the logging buffered command to specify the logging buffer as a destination for syslog messages, set the size of the logging buffer, and limit syslog messages sent to the logging buffer based on severity.

Use the show logging command to display syslog messages stored in the logging buffer.

Related Commands

To specify the device to be used for logging syslogs, use the device command in logging archive configuration mode. To return to the default, use the no form of this command.

Command Default

None

Command Modes

Logging archive configuration

Usage Guidelines

Use the device command to specify where syslogs are logged. The logs are created under the directory <device>/var/log. If the device is not configured, then all other logging archive configurations are rejected. Similarly, the configured device cannot be removed until the other logging archive configurations are removed.

It is recommended that the syslogs be archived to the harddisk because it has more capacity.

To specify the maximum file size for a log file in the archive, use the file-size command in logging archive configuration mode. To return to the default, use the no form of this command.

Command Default

size: 1 MB

Command Modes

Logging archive configuration

Usage Guidelines

Use the file-size command to specify the maximum file size that a single log file in the archive can grow to. Once this limit is reached, a new file is automatically created with an increasing serial number.

To specify the collection period for logs, use the frequency command in logging archive configuration mode. To return to the default, use the no form of this command.

Command Default

Logs are collected daily.

Command Modes

Logging archive configuration

Usage Guidelines

Use the frequency command to specify if logs are collected daily or weekly.

To specify a system logging (syslog) server host as the recipient of syslog messages, use the logging command in global configuration mode. To remove the logging command from the configuration file and delete a syslog server from the list of syslog server hosts, use the no form of this command.

Command Default

No syslog server hosts are configured as recipients of syslog messages.

Command Modes

Global configuration

Usage Guidelines

Use the logging command to identify a syslog server host to receive messages. By issuing this command more than once, you build a list of syslog servers that receive messages.

When syslog messages are sent to a syslog server, the Cisco IOS XR software includes a numerical message identifier in syslog messages. The message identifier is cumulative and sequential. The numerical identifier included in syslog messages sent to syslog servers provides a means to determine if any messages have been lost.

Use the logging trap command to limit the messages sent to snmp server.

Related Commands

To configure attributes for archiving syslogs, use the logging archive command in global configuration mode. To exit the logging archive submode, use the no form of this command.

Syntax Description

This command has no keywords or arguments.

Command Default

None

Command Modes

Global configuration

Usage Guidelines

Use the logging archive command to configure attributes for archiving syslogs. This command enters logging archive configuration mode and allows you to configure the commands in Table 1:

Note	The configuration attributes must be explicitly configured in order to use the logging archive feature.

To specify the logging buffer as a destination for system logging (syslog) messages, use the logging buffered command in global configuration mode. To remove the logging buffered command from the configuration file and cancel the use of the buffer, use the no form of this command.

Command Default

size: 307200 bytes

severity: debugging

Command Modes

Global configuration

Usage Guidelines

Use the logging buffered command to copy messages to the logging buffer. The logging buffer is circular, so newer messages overwrite older messages after the buffer is filled. This command is related to the show logging buffer command, which means that when you execute a logging buffered warnings command, it enables the logging for all the levels below the configured level, including log for LOG_ERR, LOG_CRIT, LOG_ALERT, LOG_EMERG, and LOG_WARNING messages. Use the logging buffer size to change the size of the buffer.

The value specified for the severity argument causes messages at that level and at numerically lower levels to be displayed on the console terminal. See Table 1for a list of the possible severity level keywords for the severity argument.

Related Commands

To enable logging of system logging (syslog) messages logged to the console by severity level, use the logging console command in global configuration mode. To return console logging to the default setting, use the no form of this command.

Command Default

By default, logging to the console is enabled.

severity: informational

Command Modes

Global configuration

Usage Guidelines

Use the logging console command to prevent debugging messages from flooding your screen.

The logging console is for the console terminal. The value specified for the severity argument causes messages at that level and at numerically lower levels (higher severity levels) to be displayed on the console.

Use the logging console disable command to disable console logging completely.

Use the no logging console command to return the configuration to the default setting.

Use the show logging command to display syslog messages stored in the logging buffer.

Related Commands

To disable logging of system logging (syslog) messages logged to the console, use the logging console disable command in global configuration mode. To return logging to the default setting, use the no form of this command.

Syntax Description

This command has no keywords or arguments.

Command Default

By default, logging is enabled.

Command Modes

Global configuration

Usage Guidelines

Use the logging console disable command to disable console logging completely.

Use the no logging console disable command to return the configuration to the default setting.

To enable the logging of link-status system logging (syslog) messages for logical and physical links, use the logging events link-status command in global configuration mode. To disable the logging of link status messages, use the no form of this command.

Command Default

The logging of link-status messages is enabled for physical links.

Command Modes

Global configuration

Usage Guidelines

When the logging of link-status messages is enabled, the router can generate a high volume of link-status up and down system logging messages.

Use the no logging events link-status command to enable the logging of link-status messages for physical links only, which is the default behavior.

Note	Enabling the logging events link-status (interface) command on a specific interface overrides the global configuration set using the logging events link-status command described in this section.

Related Commands

To enable the logging of link-status system logging (syslog) messages on a specific interface for virtual interfaces and subinterfaces, use the logging events link-status command in the appropriate interface or subinterface mode. To disable the logging of link status messages, use the no form of this command.

Syntax Description

This command has no keywords or arguments.

Command Default

The logging of link-status messages is disabled for virtual interfaces and subinterfaces.

Command Modes

Interface configuration

Usage Guidelines

When the logging of link-status messages is enabled, the router can generate a high volume of link-status up and down system logging messages. The logging events link-status command enables messages for virtual interfaces and subinterfaces only.

The logging events link-status command allows you to enable and disable logging on a specific interface for bundles, tunnels, and VLANs.

Use the no logging events link-status command to disable the logging of link-status messages.

Note	Enabling the logging events link-status command on a specific interface overrides the global configuration set using the logging events link-status command in global configuration mode.

To configure the type of syslog facility in which system logging (syslog) messages are sent to syslog servers, use the logging facility command in global configuration mode. To remove the logging facility command from the configuration file and disable the logging of messages to any facility type, use the no form of this command.

Command Default

type: local7

Command Modes

Global configuration

Usage Guidelines

This table describes the acceptable options for the type argument.

Use the logging command to specify a syslog server host as a destination for syslog messages.

Related Commands

To change the severity level of system logging (syslog) messages sent to the history table on the router and a Simple Network Management Protocol (SNMP) network management station (NMS), use the logging history command in global configuration mode. To remove the logging history command from the configuration and return the logging of messages to the default level, use the no form of this command.

Command Default

severity: warnings

Command Modes

Global configuration

Usage Guidelines

Logging of messages to an SNMP NMS is enabled by the snmp-server enable traps command. Because SNMP traps are inherently unreliable and much too important to lose, at least one syslog message, the most recent message, is stored in a history table on the router.

Use the logging history command to reflect the history of last 500 syslog messages. For example, when this command is issued, the last 500 syslog messages with severity less than warning message are displayed in the output of show logging history command.

Use the show logging history command to display the history table, which contains table size, message status, and message text data.

Use the logging history size command to change the number of messages stored in the history table.

The value specified for the severity argument causes messages at that severity level and at numerically lower levels to be stored in the history table of the router and sent to the SNMP NMS. Severity levels are numbered 0 to 7, with 1 being the most important message and 7 being the least important message (that is, the lower the number, the more critical the message). For example, specifying the level critical with the critical keyword causes messages at the severity level of critical (2), alerts (1), and emergencies (0) to be stored in the history table and sent to the SNMP NMS.

The no logging history command resets the history level to the default.

Related Commands

To change the number of system logging (syslog) messages that can be stored in the history table, use the logging history size command in global configuration mode. To remove the logging history size command from the configuration and return the number of messages to the default value, use the no form of this command.

Command Default

number: 1 message

Command Modes

Global configuration

Usage Guidelines

Use the logging history size command to change the number of messages that can be stored in this history table. When the history table is full (that is, when it contains the maximum number of messages specified with the command), the oldest message is deleted from the table to allow the new message to be stored.

Use the logging history command to change the severity level of syslog messages stored in the history file and sent to the SNMP server.

Related Commands

To append a hostname prefix to system logging (syslog) messages logged to syslog servers, use the logging hostnameprefix command in global configuration mode. To remove the logging hostnameprefix command from the configuration file and disable the logging host name prefix definition, use the no form of this command.

Command Default

No hostname prefix is added to the messages logged to the syslog servers.

Command Modes

Global configuration

Usage Guidelines

Use the logging hostnameprefix command to append a hostname prefix to messages sent to syslog servers from the router. You can use these prefixes to sort the messages being sent to a given syslog server from different networking devices.

Use the logging command to specify a syslog server host as a destination for syslog messages.

Related Commands

To specify the size of the local logging file, use the logging localfilesize command in global configuration mode. To remove the logging localfilesize command from the configuration file and restore the system to the default condition, use the no form of this command.

Command Default

bytes: 32000 bytes

Command Modes

Global configuration

Usage Guidelines

Use the logging localfilesize command to set the size of the local logging file.

Related Commands

To specify terminal lines other than the console terminal as destinations for system logging (syslog) messages and limit the number of messages sent to terminal lines based on severity, use the logging monitor command in global configuration mode. To remove the logging monitor command from the configuration file and disable logging to terminal lines other than the console line, use the no form of this command.

Command Default

severity: debugging

Command Modes

Global configuration

Usage Guidelines

The logging monitor is for the terminal monitoring. Use the logging monitor command to restrict the messages displayed on terminal lines other than the console line (such as virtual terminals). The value set for the severity argument causes messages at that level and at numerically lower levels to be displayed on the monitor.

Use the terminal monitor command to enable the display of syslog messages for the current terminal session.

Related Commands

To set all system logging (syslog) messages being sent to syslog servers to contain the same IP address, regardless of which interface the syslog message uses to exit the router, use the logging source-interface command in global configuration mode. To remove the logging source-interface command from the configuration file and remove the source designation, use the no form of this command.

Command Default

No source IP address is specified.

Command Modes

Global configuration

Usage Guidelines

Normally, a syslog message contains the IP address of the interface it uses to leave the networking device. Use the logging source-interface command to specify that syslog packets contain the IP address of a particular interface, regardless of which interface the packet uses to exit the networking device.

Use the logging command to specify a syslog server host as a destination for syslog messages.

Related Commands

To prevent the logging of messages to the console to indicate that commands are deprecated, use the logging suppress deprecated command in global configuration mode. To remove the logging suppress deprecated command from the configuration file, use the no form of this command.

Syntax Description

This command has no keywords or arguments.

Command Default

Console messages are displayed when deprecated commands are used.

Command Modes

Global configuration

Usage Guidelines

The logging suppress deprecated command affects messages to the console only.

To prevent the consecutive logging of more than one copy of the same system logging (syslog) message, use the logging suppress duplicates command in global configuration mode. To remove the logging suppress duplicates command from the configuration file and disable the filtering process, use the no form of this command.

Syntax Description

This command has no keywords or arguments.

Command Default

Duplicate messages are logged.

Command Modes

Global configuration

Usage Guidelines

If you use the logging suppress duplicates command during debugging sessions, you might not see all the repeated messages and could miss important information related to problems that you are attempting to isolate and resolve. In such a situation, you might consider disabling this command.

Related Commands

To specify the severity level of messages logged to system logging (syslog) servers, use the logging trap command in global configuration mode. To restore the default behavior, use the no form of this command.

Command Default

severity: informational

Command Modes

Global configuration

Usage Guidelines

Use the logging trap command to limit the logging of messages sent to syslog servers to only those messages at the specified level.

Table 1 under the “Usage Guidelines” section for the logging buffered command lists the syslog definitions that correspond to the debugging message levels.

Use the logging command to specify a syslog server host as a destination for syslog messages.

Related Commands

To modify the time-stamp format for system logging (syslog) and debug messages, use the service timestamps command in global configuration mode. To revert to the default timestamp format, use the no form of this command.

Command Default

Messages are time-stamped in the month day hh:mm:ss by default.

The default for the service timestamps debug datetime and service timestamps log datetime forms of the command with no additional keywords is to format the time in Coordinated Universal Time (UTC) without milliseconds and time zone information.

Command Modes

Global configuration

Usage Guidelines

Time stamps can be added to either debugging or syslog messages independently. The uptime keyword adds time stamps in the format hhhh:mm:ss, indicating the elapsed time in hours:minutes:seconds since the networking device last rebooted. The datetime keyword adds time stamps in the format mmm dd hh:mm:ss, indicating the date and time according to the system clock. If the system clock has not been set, the date and time are preceded by an asterisk (*), which indicates that the date and time have not been set and should be verified.

The no form of the service timestamps command causes messages to be time-stamped in the default format.

Entering the service timestamps form of this command without any keywords or arguments is equivalent to issuing the service timestamps debug uptime form of this command.

To specify the filter level for logs, use the severity command in logging archive configuration mode. To return to the default, use the no form of this command.

Command Default

Informational

Command Modes

Logging archive configuration

Usage Guidelines

Use the severity command to specify the filter level for syslog messages. All syslog messages higher in severity or the same as the configured value are logged to the archive.

Table 1 describes the acceptable severity levels for the severity argument.

To display the contents of the logging buffer, use the show logging command in EXEC mode.

Command Default

None

Command Modes

EXEC

Usage Guidelines

Use the show logging command to display the state of syslog error and event logging on the processor console. The information from the command includes the types of logging enabled and the size of the buffer.

Related Commands

To display information about the state of the system logging (syslog) history table, use the show logging history command in EXEC mode.

Syntax Description

This command has no keywords or arguments.

Command Default

None

Command Modes

EXEC

Usage Guidelines

Use the show logging history command to display information about the syslog history table, such as the table size, the status of messages, and the text of messages stored in the table. Simple Network Management Protocol (SNMP) configuration parameters and protocol activity also are displayed.

Use the logging history command to change the severity level of syslog messages stored in the history file and sent to the SNMP server.

Use the logging history size to change the number of syslog messages that can be stored in the history table.

Related Commands

To enable the display of debug command output and system logging (syslog) messages for the current terminal session, use the terminal monitor command in EXEC mode.

Command Default

None

Command Modes

EXEC

Usage Guidelines

Use the terminal monitor command to enable the display of syslog messages for the current terminal session.

Note	Syslog messages are not sent to terminal lines unless the logging monitor is enabled.

Use the terminal monitor disable command to disable the display of logging messages for the current terminal session. If the display of logging messages has been disabled, use the terminal monitor command to re-enable the display of logging messages for the current terminal session.

The terminal monitor command is set locally, and does not remain in effect after a terminal session has ended; therefore, you must explicitly enable or disable the terminal monitor command each time that you would like to monitor a terminal session.

Related Commands