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Cisco IOS Configuration Fundamentals and Network Management Command Reference, Release 12.3
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Introduction
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CFR Commands: absolute -- clock timezone
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CFR Commands: clock update-calendar -- escape-character
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CFR Commands: exception core-file -- ip ftp passive
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CFR Commands: ip ftp password -- lsr-path
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CFR Commands: memory sanity -- periodic
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CFR Commands: ping -- service sequence numbers
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CFR Commands: service slave-log -- show
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CFR Commands: show context -- show ip http server
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CFR Commands: show kron schedule -- show rtr enhanced-history
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12.3 CF CR Commands: show rtr distributions-statistics -- snmp-server enable informs
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CFR Commands: snmp-server enable traps -- statistics-distribution-interval
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CFR Commands: stopbits -- ttl ip
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CFR Commands: type dhcp - xsm vdm
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CFR Appendix: ASCII Character Set and Hex Values
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Table Of Contents
memory sanity
To perform a "sanity check" for corruption in buffers and queues, use the memory sanity command in global configuration mode. To disable this feature, use the no form of this command.
memory sanity [buffer | queue | all]
no memory sanity
Syntax Description
buffer
(Optional) Specifies checking all buffers.
queue
(Optional) Specifies checking all queues.
all
(Optional) Specifies checking all buffers and queues.
Defaults
This command is not enabled by default.
If the buffer or queue keyword is not specified, a sanity check will be performed on all buffers and queues.Command Modes
Global configuration
Command History
Usage Guidelines
When the memory sanity buffer command is enabled, a sanity check is performed on buffers when a packet buffer is allocated or when a packet buffer is returned to the buffer pool. This command also time-stamps the buffer, which may be useful when tracking the age of a buffer.
The memory sanity command can be saved in the startup configuration file and, therefore, it is not necessary to reconfigure this command each time the router is reloaded. Like the scheduler heapcheck process memory command, the memory sanity command can check for corruption in the I/O memory block.
Enabling the memory sanity command may result in slight router performance degradation.
Examples
The following example shows how to perform a sanity check for corruption in all buffers and queues:
memory sanity allRelated Commands
scheduler heapcheck process memory
Performs a "sanity check" for corruption in memory blocks when a process switch occurs.
memory scan
To enable the Memory Scan feature, use the memory scan command in global configuration mode. To restore the router configuration to the default, use the no form of this command.
memory scan
no memory scan
Syntax Description
This command has no arguments or keywords.
Defaults
This command is disabled by default.
Command Modes
Global configuration
Command History
12.0(4)XE
This command was introduced.
12.0(7)T
This command was integrated in Cisco IOS Release 12.0 T for the Cisco 7500 series only.
Usage Guidelines
The Memory Scan feature adds a low-priority background process that searches all installed dynamic random-access memory (DRAM) for possible parity errors. If errors are found in memory areas that are not in use, this feature attempts to scrub (remove) the errors. The time to complete one memory scan and scrub cycle can range from 10 minutes to several hours, depending on the amount of installed memory. The impact of the Memory Scan feature on the central processing unit (CPU) is minimal. To view the status of the memory scan feature on your router, use the show memory scan command in EXEC mode.
Examples
The following example enables the Memory Scan feature on a Cisco 7500 series router:
Router(config)# memory scanRelated Commands
memory-size iomem
To reallocate the percentage of DRAM to use for I/O memory and processor memory on Cisco 3600 series routers, use the memory-size iomem command in global configuration mode. To revert to the default memory allocation, use the no form of this command.
memory-size iomem i/o-memory-percentage
no memory-size iomem i/o-memory-percentage
Syntax Description
i/o-memory-percentage
The percentage of DRAM allocated to I/O memory. The values permitted are 10, 15, 20, 25, 30, 40, and 50. A minimum of 4 MB of memory is required for I/O memory.
Defaults
The default memory allocation is 25 percent I/O memory and 75 percent processor memory.
Note
If the smartinit process has been enabled, the default memory allocation of 25 percent to I/O does not apply. Instead, smartinit examines the network modules and then calculates the I/O memory required.
Command Modes
Global configuration
Command History
Usage Guidelines
When you specify the percentage of I/O memory in the command line, processor memory automatically acquires the remaining percentage of DRAM memory.
Examples
The following example allocates 40 percent of the DRAM memory to I/O memory and the remaining 60 percent to processor memory:
Router# configure terminalEnter configuration commands, one per line. End with CNTL/Z.Router(config)# memory-size iomem 40Router(config)# exitRouter# copy system:running-config nvram:startup-configBuilding configuration...[OK]Router# reloadrommon 1 > bootprogram load complete, entry point: 0x80008000, size: 0x32ea24Self decompressing the image : ########################################################################################## ########################################################################################## ################################################################## [OK]menu (EXEC)
To display a preconfigured user menu, use the menu command in user EXEC or privileged EXEC mode.
menu menu-name
Syntax Description
Command Modes
User EXEC
Privileged EXEC
Command History
Usage Guidelines
A user menu is a type of user interface where text descriptions of actions to be performed are displayed to the user. The user can use the menu to select services and functions without having to know the details of command-line interface (CLI) commands.
Menus can be created for users in global configuration mode, using the commands listed in the "Related Commands" section.
A menu can be invoked at either the user or privileged EXEC level, but if an item in the menu contains a privileged EXEC command, the user must be logged in at the privileged level for the command to succeed.
Examples
The following example invokes a menu named OnRamp:
Router> menu OnRampWelcome to OnRamp Internet ServicesType a number to select an option;Type 9 to exit the menu.1 Read email2 UNIX Internet access3 Resume UNIX connection6 Resume next connection9 Exit menu systemRelated Commands
menu clear-screen
To clear the terminal screen before displaying a menu, use the menu clear-screen command in global configuration mode.
menu menu-name clear-screen
Syntax Description
Defaults
Disabled
Command Modes
Global configuration
Command History
Usage Guidelines
This command uses a terminal-independent mechanism based on termcap entries defined in the router and the configured terminal type for the user. This command allows the same menu to be used on multiple types of terminals instead of having terminal-specific strings embedded within menu titles. If the termcap entry does not contain a clear string, the menu system enters 24 new lines, causing all existing text to scroll off the top of the terminal screen.
Examples
In the following example, the terminal screen is cleared before displaying the menu named Access1:
Router(config)# menu Access1 clear-screenRelated Commands
menu command
To specify underlying commands for user menus, use the menu command command in global configuration mode.
menu menu-name command menu-item {command | menu-exit}
Syntax Description
Defaults
Disabled
Command Modes
Global configuration
Command History
Usage Guidelines
Use this command to assign actions to items in a menu. Use the menu text global configuration command to assign text to items. These commands must use the same menu name and menu selection key.
The menu command command has a special keyword for the command argument, menu-exit, that is available only within menus. It is used to exit a submenu and return to the previous menu level, or to exit the menu altogether and return to the EXEC command prompt.
You can create submenus that are opened by selecting entries in another menu. Use the menu EXEC command as the command for the submenu item.
Note
When a menu allows connections (their normal use), the command for an entry activating the connection should contain a resume command, or the line should be configured to prevent users from escaping their sessions with the escape-char none command. Otherwise, when they escape from a connection and return to the menu, there will be no way to resume the session and it will sit idle until the user logs out.
Specifying the resume command as the action that is performed for a selected menu entry permits a user to resume a named connection or connect using the specified name, if there is no active connection by that name. As an option, you can also supply the connect string needed to connect initially. When you do not supply this connect string, the command uses the specified connection name.
You can also use the resume/next command, which resumes the next connection in the user's list of connections. This function allows you to create a single menu entry that steps through all of the user's connections.
Note
When a particular line should always display a menu, that line can be configured with an autocommand line configuration command. Menus can be run on a per-user basis by defining a similar autocommand command for that local username. For more information about the autocommand command, refer to the Cisco IOS Dial Technologies Configuration Guide.
Examples
In the following example, the commands to be issued when the menu user selects option 1, 2, or 3 are specified for the menu named Access1:
menu Access1 command 1 tn3270 vms.cisco.commenu Access1 command 2 rlogin unix.cisco.commenu Access1 command 3 menu-exitThe following example allows a menu user to exit a menu by entering Exit at the menu prompt:
menu Access1 text Exit Exitmenu Access1 command Exit menu-exit
Related Commands
menu default
To specify the menu item to use as the default, use the menu default command in global configuration mode.
menu menu-name default menu-item
Syntax Description
menu-name
Name of the menu. You can specify a maximum of 20 characters.
menu-item
Number, character, or string key of the item to use as the default.
Defaults
Disabled
Command Modes
Global configuration
Command History
Usage Guidelines
Use this command to specify which menu entry is used when the user presses Enter without specifying an item. The menu entries are defined by the menu command and menu text global configuration commands.
Examples
In the following example, the menu user exits the menu when pressing Enter without selecting an item:
menu Access1 9 text Exit the menumenu Access1 9 command menu-exitmenu Access1 default 9Related Commands
menu line-mode
To require the user to press Enter after specifying an item, use the menu line-mode command in global configuration mode.
menu menu-name line-mode
Syntax Description
Defaults
Enabled for menus with more than nine items. Disabled for menus with nine or fewer items.
Command Modes
Global configuration
Command History
Usage Guidelines
In a menu of nine or fewer items, you ordinarily select a menu item by entering the item number. In line mode, you select a menu entry by entering the item number and pressing Enter. Line mode allows you to backspace over the selected number and enter another number before pressing Enter to issue the command.
This option is activated automatically when more than nine menu items are defined but also can be configured explicitly for menus of nine or fewer items.
In order to use strings as keys for items, the menu line-mode command must be configured.
Examples
In the following example, the line-mode option is enabled for the menu named Access1:
menu Access1 line-modeRelated Commands
menu options
To set options for items in user menus, use the menu options command in global configuration mode.
menu menu-name options menu-item {login | pause}
Syntax Description
Defaults
Disabled
Command Modes
Global configuration
Command History
Usage Guidelines
Use the menu command and menu text global configuration commands to define a menu entry.
Examples
In the following example, a login is required before issuing the command specified by menu entry 3 of the menu named Access1:
menu Access1 options 3 loginRelated Commands
menu prompt
To specify the prompt for a user menu, use the menu prompt command in global configuration mode.
menu menu-name prompt d prompt d
Syntax Description
Defaults
Disabled
Command Modes
Global configuration
Command History
Usage Guidelines
Press Enter after entering the first delimiter. The router will prompt you for the text of the prompt. Enter the text followed by the delimiter, and press Enter.
Use the menu command and menu text commands to define the menu selections.
Examples
In the following example, the prompt for the menu named Access1 is configured as "Select an item.":
Router(config)# menu Access1 prompt /Enter TEXT message. End with the character '/'.Select an item. /Router(config)#Related Commands
menu single-space
To display menu items single-spaced rather than double-spaced, use the menu single-space command in global configuration mode.
menu menu-name single-space
Syntax Description
Defaults
Enabled for menus with more than nine items; disabled for menus with nine or fewer items.
Command Modes
Global configuration
Command History
Usage Guidelines
When more than nine menu items are defined, the menu is displayed single-spaced. To configure the menus with nine or fewer items to display single-spaced, use this command.
Examples
In the following example, single-spaced menu items are displayed for the menu named Access1:
menu Access1 single-spaceRelated Commands
menu status-line
To display a line of status information about the current user at the top of a menu, use the menu status-line command in global configuration mode.
menu menu-name status-line
Syntax Description
Defaults
Disabled
Command Modes
Global configuration
Command History
Usage Guidelines
This command displays the status information at the top of the screen before the menu title is displayed. This status line includes the router's host name, the user's line number, and the current terminal type and keymap type (if any).
Examples
In the following example, status information is enabled for the menu named Access1:
menu Access1 status-lineRelated Commands
menu text
To specify the text of a menu item in a user menu, use the menu text command in global configuration mode.
menu menu-name text menu-item menu-text
Syntax Description
Defaults
No text appears for the menu item.
Command Modes
Global configuration
Command History
Usage Guidelines
Use this command to assign text to items in a menu. Use the menu command command to assign actions to items. These commands must use the same menu name and menu selection key.
You can specify a maximum of 18 items in a menu.
Examples
In the following example, the descriptive text for the three entries is specified for options 1, 2, and 3 in the menu named Access1:
menu Access1 text 1 IBM Information Systemsmenu Access1 text 2 UNIX Internet Accessmenu Access1 text 3 Exit menu systemRelated Commands
menu title
To create a title (banner) for a user menu, use the menu title command in global configuration mode.
menu menu-name title d menu-title d
Syntax Description
Defaults
The menu does not have a title.
Command Modes
Global configuration
Command History
Usage Guidelines
The menu title command must use the same menu name used with the menu text and menu command commands used to create a menu.
You can position the title of the menu horizontally by preceding the title text with blank characters. You can also add lines of space above and below the title by pressing Enter.
Follow the title keyword with one or more blank characters and a delimiting character of your choice. Then enter one or more lines of text, ending the title with the same delimiting character. You cannot use the delimiting character within the text of the message.
When you are configuring from a terminal and are attempting to include special control characters, such as a screen-clearing string, you must use Ctrl-V before the special control characters so that they are accepted as part of the title string. The string ^[[H^[[J is an escape string used by many VT100-compatible terminals to clear the screen. To use a special string, you must enter Ctrl-V before each escape character.
You also can use the menu clear-screen global configuration command to clear the screen before displaying menus and submenus, instead of embedding a terminal-specific string in the menu title. The menu clear-screen command allows the same menu to be used on different types of terminals.
Examples
In the following example, the title that will be displayed is specified when the menu named Access1 is invoked. Press Enter after the second slash (/) to display the prompt.
Router(config)# menu Access1 title /^[[H^[[JEnter TEXT message. End with the character '/'.Welcome to Access1 Internet ServicesType a number to select an option;Type 9 to exit the menu./Router(config)#Related Commands
microcode (7000/7500)
To specify the location of the microcode that you want to download from Flash memory into the writable control store (WCS) on Cisco 7000 series (including RSP based routers) or Cisco 7500 series routers, use the microcode command in global configuration mode. To load the microcode bundled with the system image, use the no form of this command.
microcode interface-type {flash-filesystem:filename [slot] | rom | system [slot]]}
no microcode interface-type {flash-filesystem:filename [slot] | rom | system [slot]}
Syntax Description
Defaults
The default is to load from the microcode bundled in the system image.
Command Modes
Global configuration
Command History
Usage Guidelines
If you do not use the microcode reload command after using the microcode command, the microcode reload command will be written to the configuration file automatically.
When using Dual RSPs for simple hardware backup, ensure that the master and slave RSP card contain the same microcode image in the same location when the router is to load the interface processor microcode from a Flash file system. Thus, if the slave RSP becomes the master, it will be able to find the microcode image and download it to the interface processor.
Examples
In the following example, all FIP cards will be loaded with the microcode found in Flash memory file fip.v141-7 when the system is booted, when a card is inserted or removed, or when the microcode reload global configuration command is issued. The configuration is then written to the startup configuration file.
Router(config)# microcode fip slot0:fip.v141-7Router(config)# endRouter# copy system:running-config nvram:startup-configRelated Commands
more flh:logfile
Displays the system console output generated during the Flash load helper operation.
microcode (12000)
To load a Cisco IOS software image on a line card from Flash memory or the GRP card on a Cisco 12000 series Gigabit Switch Router (GSR), use the microcode command in global configuration mode. To load the microcode bundled with the GRP system image, use the no form of this command.
microcode {oc12-atm | oc12-pos | oc3-pos4} {flash file-id [slot] | system [slot]}
no microcode {oc12-atm | oc12-pos | oc3-pos4} [flash file-id [slot] | system [slot]]
Syntax Description
Defaults
The default is to load the image from the GRP card (system).
Command Modes
Global configuration
Command History
Usage Guidelines
In addition to the Cisco IOS image that resides on the GRP card, each line card on a Cisco 12000 series has a Cisco IOS image. When the router is reloaded, the specified image is loaded onto the GRP card and then automatically downloaded to all the line cards.
Normally, you want the same Cisco IOS image on the GRP card and all line cards. However, if you want to upgrade a line card with a new version of microcode for testing or to fix a defect, you might need to load a Cisco IOS image that is different from the one on the line card. Additionally, you might need to load a new image on the line card to work around a problem that is affecting only one of the line cards.
To load a Cisco IOS image on a line card, first use the copy tftp command to download the Cisco IOS image to a slot on one of the PCMCIA Flash memory cards. Then use the microcode command to download the image to the line card, followed by the microcode reload command to start the image. Immediately after you enter the microcode reload command and press Return, the system reloads all microcode. Global configuration mode remains enabled. After the reloading is complete, enter the exit command to return to the EXEC system prompt.
To verify that the correct image is running on the line card, use the execute-on slot slot show version command.
For additional information on GSR configuration, refer to the documentation specific to your Cisco IOS software release.
Examples
In the following example, the Cisco IOS software image in slot 0 is downloaded to the line card in slot 10. This software image is used when the system is booted, a line card is inserted or removed, or the microcode reload global configuration command is issued.
Router(config)# microcode oc3-POS-4 flash slot0:fip.v141-7 10Router(config)# microcode reload 10In this example, the user would issue the execute-on slot 10 show version command to verify that the correct version is loaded.
Related Commands
microcode (7200)
To configure a default override for the microcode that is downloaded to the hardware on a Cisco 7200 series router, use the microcode command in global configuration mode. To revert to the default microcode for the current running version of the Cisco IOS software, use the no form of this command.
microcode {ecpa | pcpa} location
no microcode {ecpa | pcpa}
Syntax Description
ecpa
ESCON Channel Port Adapter (CPA) interface.
pcpa
Parallel CPA interface.
location
Location of microcode, including the device and filename.
Defaults
If the default or no form of the command is specified, the driver uses the default microcode for the current running version of the Cisco IOS software.
Command Modes
Global configuration
Command History
Usage Guidelines
If there are any default overrides when the configuration is written, then the microcode reload command will be written to the configuration automatically. This action enables the configured microcode to be downloaded at system startup.
The CPA microcode image is preloaded on Flash memory cards for Cisco 7200-series routers for Cisco IOS Release 11.3(3)T and later releases. You may be required to copy a new image to Flash memory when a new microcode image becomes available.
For more information on the CPA configuration and maintenance, refer to the "Configuring Cisco Mainframe Channel Connection Adapters" chapter in the Cisco IOS Bridging and IBM Networking Configuration Guide.
Examples
The following example instructs the Cisco IOS software to load the microcode from an individual microcode image that is stored as a file on the Flash card inserted in Flash card slot 0:
microcode ecpa slot0:xcpa26-1Related Commands
microcode reload (7200)
Resets and reloads the specified hardware in a Cisco 7200 series router.
show microcode
Displays microcode information.
microcode reload (7000/7500)
To reload the processor card on the Cisco 7000 series with RSP7000 or Cisco 7500 series routers, use the microcode reload command in global configuration mode.
microcode reload
Syntax Description
This command has no arguments or keywords.
Defaults
No default behaviors or values.
Command Modes
Global configuration
Command History
Usage Guidelines
This command reloads the microcode without rebooting the router. Immediately after you enter the microcode reload command and press Return, the system reloads all microcode. Global configuration mode remains enabled.
Note
Examples
In the following example, all controllers are reset, and the microcode specified in the current configuration is loaded:
Router(config)# microcode reloadRelated Commands
microcode (7000/7500)
Specifes the location from where microcode should be loaded when the microcode reload command is executed on RSP-based routers.
microcode reload (7200)
To reload the Cisco IOS microcode image on an ESCON CPA card in the Cisco 7200 series router, use the microcode reload command in privileged EXEC mode.
microcode reload {all | ecpa [slot slot-number] | pcpa [slot slot-number]}
Syntax Description
Command Modes
Privileged EXEC
Command History
Usage Guidelines
Hardware types that do not support downloadable microcode are unaffected by the microcode reload all command.
You will be prompted for confirmation before the microcode reload command is executed.
Examples
The following example reloads the ESCON CPA microcode in slot 5 with the currently configured microcode:
Router# microcode reload ecpa slot 5Related Commands
microcode reload (12000)
To reload the Cisco IOS image from a line card on Cisco 12000 series routers, use the microcode reload command in global configuration mode.
microcode reload [slot-number]
Syntax Description
Command Modes
Global configuration
Command History
Usage Guidelines
In addition to the Cisco IOS image that resides on the GRP card, each line card on Cisco 12000 series routers has a Cisco IOS image. When the router is reloaded, the specified Cisco IOS image is loaded onto the GRP card and automatically downloaded to all the line cards.
Normally, you want the same Cisco IOS image on the GRP card and all line cards. However, if you want to upgrade a line card with a new version of microcode for testing or to fix a defect, you might need to load a different Cisco IOS image. Additionally, you might need to load a new image on the line card to work around a problem affecting only one of the line cards.
To load a Cisco IOS image on a line card, first use the copy tftp command to download the Cisco IOS image to a slot on one of the PCMCIA Flash memory cards. Then use the microcode command to download the image to the line card, followed by the microcode reload command to start the image. To verify that the correct image is running on the line card, use the execute-on slot slot show version command.
For additional information on GSR configuration, refer to the "Observing System Startup and Performing a Basic Configuration" chapter in the Cisco 12000 series installation and configuration guides.
The microcode reload (12000) command allows you to issue another command immediately.
Note
Examples
In the following example, the mirocode firmware is reloaded on the line card in slot 10:
Router(config)# microcode reload 10Related Commands
microcode (12000)
Loads a Cisco IOS software image on a line card from Flash memory or the GRP card on a Cisco 12000 series GSR.
mkdir
To create a new directory in a Class C Flash file system, use the mkdir command in EXEC mode.
mkdir directory
Syntax Description
Command Modes
EXEC
Command History
Usage Guidelines
This command is only valid on Class C Flash file systems.
If you do not specify the directory name in the command line, the router prompts you for it.
Examples
The following example creates a directory named newdir:
Router# mkdir newdirMkdir file name [newdir]?Created dir flash:newdirRouter# dirDirectory of flash:2 drwx 0 Mar 13 1993 13:16:21 newdir8128000 bytes total (8126976 bytes free)Related Commands
dir
Displays a list of files on a file system.
rmdir
Removes an existing directory in a Class C Flash file system.
mop device-code
To identify the type of device sending Maintenance Operation Protocol (MOP) System Identification (sysid) messages and request program messages, use the mop device-code command in global configuration mode. To set the identity to the default value, use the no form of this command.
mop device-code {cisco | ds200}
no mop device-code {cisco | ds200}
Syntax Description
Defaults
Cisco device code
Command Modes
Global configuration
Command History
Usage Guidelines
The sysid messages and request program messages use the identity information indicated by this command.
Examples
The following example identifies a DECserver 200 device as sending MOP sysid and request program messages:
mop device-code ds200Related Commands
mop sysid
Enables an interface to send out periodic MOP system identification messages.
mop retransmit-timer
To configure the length of time that the Cisco IOS software waits before resending boot requests to a Maintenance Operation Protocol (MOP) server, use the mop retransmit-timer command in global configuration mode. To reinstate the default value, use the no form of this command.
mop retransmit-timer seconds
no mop retransmit-timer
Syntax Description
seconds
Sets the length of time (in seconds) that the software waits before resending a message. The value is a number from 1 to 20.
Defaults
4 seconds
Command Modes
Global configuration
Command History
Usage Guidelines
By default, when the software sends a request that requires a response from a MOP boot server and the server does not respond, the message is re-sent after 4 seconds. If the MOP boot server and router are separated by a slow serial link, it might take longer than 4 seconds for the software to receive a response to its message. Therefore, you might want to configure the software to wait longer than 4 seconds before resending the message if you are using such a link.
Examples
In the following example, if the MOP boot server does not respond within 10 seconds after the router sends a message, the server will resend the message:
mop retransmit-timer 10Related Commands
mop device-code
Identifies the type of device sending MOP sysid messages and requests program messages.
mop enabled
Enables an interface to support the MOP.
mop retries
To configure the number of times the Cisco IOS software will resend boot requests to a Maintenance Operation Protocol (MOP) server, use the mop retries command in global configuration mode. To reinstate the default value, use the no form of this command.
mop retries count
no mop retries
Syntax Description
count
Indicates the number of times the software will resend a MOP boot request. The value is a number from 3 to 24. The default is 8.
Defaults
8 times
Command Modes
Global configuration
Command History
Examples
In the following example, the software will attempt to resend a message to an unresponsive host 11 times before declaring a failure:
Router(config)# mop retries 11Related Commands
more
To display a file, use the more command in EXEC mode.
more [/ascii | /binary | /ebcdic] file-url
Syntax Description
Command Modes
EXEC
Command History
Usage Guidelines
The more system:running-config command displays the same output as the show running-config command. The more nvram:startup-config command replaces the show startup-config command and the show configuration command.
You can use this command to display configuration files, as follows:
•
•
These commands show the version number of the software used when you last changed the configuration file.
You can display files on remote systems using the more command.
Examples
The following partial sample output displays the configuration file named startup-config in NVRAM:
Router# more nvram:startup-config!! No configuration change since last restart! NVRAM config last updated at 02:03:26 PDT Thu Oct 2 1997!version 12.1service timestamps debug uptimeservice timestamps log uptimeservice password-encryptionservice udp-small-serversservice tcp-small-servers...endThe following is partial sample output from the more nvram:startup-config command when the configuration file has been compressed:
Router# more nvram:startup-configUsing 21542 out of 65536 bytes, uncompressed size = 142085 bytes!version 12.1service compress-config!hostname rose!...The following partial sample output displays the running configuration:
Router2# more system:running-configBuilding configuration...Current configuration:!version 12.1no service udp-small-serversno service tcp-small-servers!hostname Router2!...!endRelated Commands
more <url> begin
To search the output of any more command, use the more url | begin command in EXEC mode. This command begins unfiltered output of the more command with the first line that contains the regular expression you specify.
more url | begin regular-expression
Syntax Description
Command Modes
User EXEC
Privileged EXEC
Command History
11.3 AA
The more command was introduced.
12.0(1)T
This extension of the more command was introduced.
Usage Guidelines
The regular-expression argument is case sensitive and allows for complex matching requirements.
You can specify a new search at every --More-- prompt.
To search the remaining output of the more command, use the following command at the --More-- prompt:
/regular-expression
To filter the remaining output of the more command, use one of the following commands at the --More-- prompt:
-regular-expression
+regular-expression
When output volume is large, the search can produce long lists of output. To interrupt the output, press Ctrl-^ (Ctrl-Shift-6) or Ctrl-Z.
Note
Because prior output is not saved, you cannot search or filter backward through prior output.
Examples
The following is partial sample output of the more nvram:startup-config | begin command that begins unfiltered output with the first line that contain the regular expression "ip." At the --More-- prompt, the user specifies a filter to exclude output lines that contain the regular expression "ip."
router# more nvram:startup-config | begin ipip subnet-zeroip domain-name cisco.comip name-server 198.92.30.32ip name-server 171.69.2.132!isdn switch-type primary-5ess...interface Ethernet1ip address 5.5.5.99 255.255.255.0--More---ipfiltering...media-type 10BaseT!interface Serial0:23encapsulation frame-relayno keepalivedialer string 4001dialer-group 1isdn switch-type primary-5essno fair-queueRelated Commands
more <url> exclude
To filter more command output so that it excludes lines that contain a particular regular expression, use the more exclude command in EXEC mode.
more url | exclude regular-expression
Syntax Description
Command Modes
EXEC
Command History
11.3 AA
The more command was introduced.
12.0(1)T
This extension of the more command was introduced.
Usage Guidelines
The regular-expression argument is case sensitive and allows for complex matching requirements.
You can specify a new search at any --More-- prompt. To search the remaining output of the more command, use the following command at the --More-- prompt:
/regular-expression
When output volume is large, the search can produce long lists of output. To interrupt the output, press Ctrl-^ (Ctrl-Shift-6) or Ctrl-Z.
Because prior output is not saved, you cannot search or filter backward through prior output.
Examples
The following is partial sample output of the more nvram:startup-config | exclude command. The use of | exclude service in the command specifies a filter that excludes lines that contain the regular expression "service." At the --More-- prompt, the user searches for the regular expression "Dialer1," which continues filtered output with the first line that contains "Dialer1."
router# more nvram:startup-config | exclude service!version 12.0!hostname router!boot system flashno logging buffered!ip subnet-zeroip domain-name cisco.com...--More--/Dialer1filtering...interface Dialer1no ip addressno ip directed-broadcastdialer in-bandno cdp enableRelated Commands
more <url> include
To filter more command output so that it displays only lines that contain a particular regular expression, use the more include command in EXEC mode.
more url | include regular-expression
Syntax Description
Command Modes
EXEC
Command History
11.3 AA
The more command was introduced.
12.0(1)T
This extension of the more command was introduced.
Usage Guidelines
The regular-expression argument is case sensitive and allows for complex matching requirements.
You can specify a new search at any --More-- prompt. To search the remaining output of the more command, use the following syntax at the --More-- prompt:
/regular-expression
When output volume is large, the search can produce long lists of output. To interrupt the output, press Ctrl-^ (Ctrl-Shift-6) or Ctrl-Z.
Because prior output is not saved, you cannot search or filter backward through prior output.
Examples
The following is partial sample output of the more nvram:startup-config | include command. It only displays lines that contain the regular expression "ip."
router# more nvram:startup-config | include ipip subnet-zeroip domain-name cisco.comip name-server 198.92.30.32ip name-server 171.69.2.132description ip address 172.21.53.199 255.255.255.0ip address 172.21.53.199 255.255.255.0Related Commands
motd-banner
To enable the display of message-of-the-day (MOTD) banners on the specified line or lines, use the motd-banner command in line configuration mode. To suppress the MOTD banners on the specified line or lines, use the no form of this command.
motd-banner
no motd-banner
Syntax Description
This command has no arguments or keywords.
Defaults
Enabled on all lines.
Command Modes
Line configuration
Command History
Usage Guidelines
This command determines whether the router will display the MOTD banner when an EXEC session is created on the specified line or lines. The MOTD banner is defined with the banner motd global configuration command. By default, the MOTD banner is enabled on all lines. Disable the MOTD banner on specific lines using the no motd-banner line configuration command.
The MOTD banners can also be disabled by the no exec-banner line configuration command, which disables both MOTD banners and EXEC banners on a line. If the no exec-banner command is configured on a line, the MOTD banner will be disabled regardless of whether the motd-banner command is enabled or disabled. Table 34 summarizes the effects of the exec-banner command and the motd-banner command.
Table 34 Banners Displayed Based On exec-banner and motd-banner Combinations
MOTD banner
EXEC banner
None
EXEC banner
None
For reverse Telnet connections, the EXEC banner is never displayed. Instead, the incoming banner is displayed. The MOTD banner is displayed by default, but it is disabled if either the no exec-banner command or no motd-banner command is configured. Table 35 summarizes the effects of the exec-banner command and the motd-banner command for reverse Telnet connections.
Examples
The following example suppresses the MOTD banner on vty lines 0 through 4:
line vty 0 4no motd-bannerRelated Commands
name-connection
To assign a logical name to a connection, use the name-connection command in user EXEC mode.
name-connection
Syntax Description
This command has no arguments or keywords.
Defaults
No logical name is defined.
Command Modes
User EXEC
Command History
Usage Guidelines
This command can be useful for keeping track of multiple connections.
You are prompted for the connection number and name to assign. The where command displays a list of the assigned logical connection names.
Examples
The following example assigns the logical name blue to the connection:
Router> whereConn Host Address Byte Idle Conn Name* 1 doc-2509 172.30.162.131 0 0 doc-2509Router> name-connectionConnection number: 1Enter logical name: blueConnection 1 to doc-2509 will be named "BLUE" [confirm]Related Commands
no menu
To delete a user menu from the configuration file, use the no menu command in global configuration mode.
no menu menu-name
Syntax Description
Defaults
No default behavior or values.
Command Modes
Global configuration
Command History
Usage Guidelines
Use this command to remove any menu commands for a particular menu from the configuration file.
As with all global configuration commands, this command will only effect the startup configuration file when you save the running configuration using the copy running-config startup-config EXEC command.
Examples
The following example deletes the menu named Access1:
no menu Access1Related Commands
no snmp-server
To disable Simple Network Management Protocol (SNMP) agent operation, use the no snmp-server command in global configuration mode.
no snmp-server
Syntax Description
This command has no arguments or keywords.
Defaults
No default behavior or values.
Command Modes
Global configuration
Command History
Usage Guidelines
This command disables all running versions of SNMP (SNMPv1, SNMPv2C, and SNMPv3) on the device.
Examples
The following example disables the current running version of SNMP:
Router(config)# no snmp-servernotify
To enable terminal notification about pending output from other Telnet connections, use the notify command in line configuration mode. To disable notifications, use the no form of this command.
notify
no notify
Syntax Description
This command has no arguments or keywords.
Defaults
Disabled
Command Modes
Line configuration
Command History
Usage Guidelines
This command sets a line to inform a user that has multiple, concurrent Telnet connections when output is pending on a connection other than the current one.
Examples
In the following example, notification of pending output from connections is enabled on virtual terminal lines 0 to 4:
Router(config)# line vty 0 4Router(config-line)# notifyRelated Commands
terminal notify
Configures a line to inform a user that has multiple, concurrent Telnet connections when output is pending on a connection other than the current one.
ntp access-group
To control access to the Network Time Protocol (NTP) services on the system, use the ntp access-group command in global configuration mode. To remove access control to the NTP services, use the no form of this command.
ntp access-group {query-only | serve-only | serve | peer} access-list-number
no ntp [access-group {query-only | serve-only | serve | peer}
Syntax Description
Defaults
No access control (full access granted to all systems)
Command Modes
Global configuration
Command History
Usage Guidelines
The access group options are scanned in the following order from least restrictive to most restrictive:
1.
2.
3.
4.
Access is granted for the first match that is found. If no access groups are specified, all access is granted to all sources. If any access groups are specified, only the specified access is granted. This facility provides minimal security for the time services of the system. However, it can be circumvented by a determined programmer. If tighter security is desired, use the NTP authentication facility.
The NTP service can be activated by entering any ntp command. When you use the ntp access-group command, the NTP service is activated (if it has not already been activated) and access control to NTP services is configured simultaneously.
In the no form of any ntp command, all the keywords are optional. When you enter the no ntp access-control command, only access control to NTP services is removed. The NTP service itself remains active, along with any other functions you previously configured.
To terminate NTP service on a device, you must enter the no ntp command without keywords. For example, if you previously issued the ntp access-group command and you now want to remove not only the access group, but all NTP functions from the device, use the no ntp command without any keywords. This ensures that all NTP functions are removed and that the NTP service is also terminated.
Examples
The following example shows how to configure a system to allow itself to be synchronized by a peer from access list 99. However, the system restricts access to allow only time requests from access list 42.
Router(config)# ntp access-group peer 99Router(config)# ntp access-group serve-only 42The following example shows how to remove all the configured NTP options and disable the ntp server:
Router(config)# no ntpRelated Commands
access-list
Configures the access list mechanism for filtering frames by protocol type or vendor code.
ntp authenticate
To enable Network Time Protocol (NTP) authentication, use the ntp authenticate command in global configuration mode. To disable the function, use the no form of this command.
ntp authenticate
no ntp [authenticate]
Syntax Description
This command has no arguments or keywords.
Defaults
No authentication
Command Modes
Global configuration
Command History
Usage Guidelines
Use this command if you want authentication. If this command is specified, the system will not synchronize to a system unless it carries one of the authentication keys specified in the ntp trusted-key global configuration command.
The NTP service can be activated by entering any ntp command. When you use the ntp authenticate command, the NTP service is activated (if it has not already been activated) and NTP authentication is enabled simultaneously.
In the no form of any ntp command, all the keywords are optional. When you enter the no ntp authenticate command, only the NTP authentication is removed from the NTP service. The NTP service itself remains active, along with any other functions you previously configured.
To terminate NTP service on a device, you must enter the no ntp command without keywords. For example, if you previously issued the ntp authenticate command and you now want to disable not only the authentication, but all NTP functions from the device, use the no ntp command without any keywords. This ensures that all NTP functions are removed and that the NTP service is also terminated.
Examples
The following example shows how to configure the system to synchronize only to systems that provide authentication key 42 in their NTP packets:
Router(config)# ntp authenticateRouter(config)# ntp authentication-key 42 md5 aNiceKeyRouter(config)# ntp trusted-key 42The following example shows how to remove all the configured NTP options and disable the ntp server:
Router(config)# no ntpRelated Commands
ntp authentication-key
Defines an authentication key for NTP.
ntp trusted-key
Authenticates the identity of a system to which NTP will synchronize.
ntp authentication-key
To define an authentication key for Network Time Protocol (NTP), use the ntp authentication-key command in global configuration mode. To remove the authentication key for NTP, use the no form of this command.
ntp authentication-key number md5 value
no ntp [authentication-key]
Syntax Description
Defaults
No authentication key is defined for NTP.
Command Modes
Global configuration
Command History
Usage Guidelines
Use this command to define authentication keys for use with other NTP commands in order to provide a higher degree of security.
Note
The NTP service can be activated by entering any ntp command. When you use the ntp authentication-key command, the NTP service is activated (if it has not already been activated) and the NTP authentication key is defined simultaneously.
In the no form of any ntp command, all the keywords are optional. When you enter the no ntp authentication-key command, only the NTP authentication key is removed from the NTP service. The NTP service itself remains active, along with any other functions you previously configured.
To terminate NTP service on a device, you must enter the no ntp command without keywords. For example, if you previously issued the ntp authentication-key command and you now want to remove not only the authentication key, but all NTP functions from the device, use the no ntp command without any keywords. This ensures that all NTP functions are removed and that the NTP service is also terminated.
Examples
The following example shows how to configure the system to synchronize only to systems providing authentication key 42 in their NTP packets:
Router(config)# ntp authenticateRouter(config)# ntp authentication-key 42 md5 aNiceKeyRouter(config)# ntp trusted-key 42The following example shows how to remove all the configured NTP options and disable the ntp server:
Router(config)# no ntpRelated Commands
ntp broadcast client
To configure a device to receive Network Time Protocol (NTP) broadcast messages on a specified interface, use the ntp broadcast client command in interface configuration mode. To disable this capability, use the no form of this command.
ntp broadcast client
no ntp broadcast [client]
Syntax Description
This command has no arguments or keywords.
Defaults
Disabled
Command Modes
Interface configuration
Command History
Usage Guidelines
Use this command to allow the system to listen to broadcast packets on an interface-by-interface basis.
The NTP service can be activated by entering any ntp command. When you use the ntp broadcast client command, the NTP service is activated (if it has not already been activated) and the device is configured to receive NTP broadcast packets on a specified interface simultaneously.
In the no form of any ntp command, all the keywords are optional. When you enter the no ntp broadcast client command, only the broadcast client configuration is removed from the NTP service. The NTP service itself remains active, along with any other functions you previously configured.
To terminate NTP service on a device, you must enter the no ntp command without keywords. For example, if you previously issued the ntp broadcast client command and you now want to remove not only the broadcast client capability, but all NTP functions from the device, use the no ntp command without any keywords. This ensures that all NTP functions are removed and that the NTP service is also terminated.
Examples
In the following example, the system is configured to receive (listen to) NTP broadcasts on Ethernet interface 1:
Router(config)# interface ethernet 1Router(config-if)# ntp broadcast clientThe following example shows how to remove all the configured NTP options and disable the ntp server:
Router(config)# no ntpRelated Commands
ntp broadcast
To configure the options for broadcasting Network Time Protocol (NTP) traffic, use the ntp broadcast command in interface configuration mode. To disable this capability, use the no form of this command.
ntp broadcast [client] [destination {ip-address | hostname}] [key broadcast-key] [version number]
no ntp [broadcast]
Syntax Description
Defaults
Disabled
Command Modes
Interface configuration
Command History
Usage Guidelines
The NTP service can be activated by entering any ntp command. When you use the ntp broadcast command, the NTP service is activated (if it has not already been activated) and the options are configured for sending NTP traffic simultaneously.
In the no form of any ntp command, all the keywords are optional. When you enter the no ntp broadcast command, only the configuration to send NTP broadcast packets on a specified interface is removed from the NTP service. The NTP service itself remains active, along with any other functions you previously configured.
To terminate NTP service on a device, you must enter the no ntp command without keywords. For example, if you previously issued the ntp broadcast command and you now want to remove not only the broadcast capability, but all NTP functions from the device, use the no ntp command without any keywords. This ensures that all NTP functions are removed and that the NTP service is also terminated.
Examples
The following example shows how to configures Ethernet interface 0 to send NTP version 2 broadcasts:
Router(config)# interface ethernet 0Router(config-if)# ntp broadcast version 2The following example shows how to remove all the configured NTP options and disable the ntp server:
Router(config)# no ntpRelated Commands
ntp broadcastdelay
To set the estimated round-trip delay between the Cisco IOS software and a Network Time Protocol (NTP) broadcast server, use the ntp broadcastdelay command in global configuration mode. To revert to the default value, use the no form of this command.
ntp broadcastdelay microseconds
no ntp [broadcastdelay]
Syntax Description
microseconds
Estimated round-trip time (in microseconds) for NTP broadcasts. The range is from 1 to 999999.
Defaults
3000 microseconds
Command Modes
Global configuration
Command History
Usage Guidelines
Use this command when the router is configured as a broadcast client and the round-trip delay on the network is other than 3000 microseconds.
The NTP service can be activated by entering any ntp command. When you use the ntp broadcastdelay command, the NTP service is activated (if it has not already been activated) and the estimated round-trip delay between the Cisco IOS software and an NTP broadcast server is set simultaneously.
In the no form of any ntp command, all the keywords are optional. When you enter the no ntp broadcastdelay command, only the estimated round-trip delay between the Cisco IOS software and an NTP broadcast server is removed from the NTP service. The NTP service itself remains active, along with any other functions you previously configured.
To terminate NTP service on a device, you must enter the no ntp command without keywords. For example, if you previously issued the ntp broadcastdelay command and you now want to remove not only the delay setting, but all NTP functions from the device, use the no ntp command without any keywords. This ensures that all NTP functions are removed and that the NTP service is also terminated.
Examples
The following example shows how to set the estimated round-trip delay between a router and the broadcast client to 5000 microseconds:
Router(config)# ntp broadcastdelay 5000The following example shows how to remove all the configured NTP options and disable the ntp server:
Router(config)# no ntpRelated Commands
ntp broadcast
Configures the specified interface to send NTP broadcast packets.
ntp broadcast client
Configures the specified interface to receive NTP broadcast packets.
ntp clock-period
Caution
As NTP compensates for the error in the software clock, it keeps track of the correction factor for this error. When the value for the clock period needs to be adjusted, the system automatically enters the correct value into the running configuration. To remove the automatically generated value for the clock period, use the no form of this command.
ntp clock-period value
no ntp [clock-period value]
Syntax Description
value
Amount of time to add to the software clock for each clock hardware tick (this value is multiplied by 2-32).
Defaults
17179869 2-32 seconds (4 milliseconds)
Command Modes
Global configuration
Command History
Usage Guidelines
Do not manually set a value for the NTP clock-period.
If the system has automatically entered a value for the clock period into the running configuration, NTP synchronizes faster after the system is restarted when the copy running-config startup-config command has been entered to save the configuration to NVRAM.
The NTP service can be activated by entering any ntp command. When you use the ntp clock-period command, the NTP service is activated (if it has not already been activated) and the system automatically saves the correct value into the running configuration simultaneously.
In the no form of any ntp command, all the keywords are optional. When you enter the no ntp clock-period command, only the automatically generated value is removed. The NTP service itself remains active, along with any other functions you previously configured.
To terminate NTP service on a device, you must enter the no ntp command without keywords. For example, if you want to remove not only the clock period, but all NTP functions from the device, use the no ntp command without any keywords. This ensures that all NTP functions are removed and that the NTP service is also terminated.
Examples
The following example shows a typical difference between the values of the NTP clock-period setting in the running configuration and in the startup configuration:
Router# show startup-config | include clock-periodntp clock-period 17180239Router# show running-config | include clock-periodntp clock-period 17180255The following example shows how to remove the automatically generated value for the clock period from the running configuration:
Router(config)# no ntp clock-periodThe following example shows how to remove all the configured NTP options and disable the ntp server:
Router(config)# no ntpntp disable
To prevent an interface from receiving Network Time Protocol (NTP) packets, use the ntp disable command in interface configuration mode. To enable receipt of NTP packets on an interface, use the no form of this command.
ntp disable
no ntp [disable]
Syntax Description
This command has no arguments or keywords.
Defaults
Enabled
Command Modes
Interface configuration
Command History
Usage Guidelines
This command provides a simple method of access control.
The NTP service can be activated by entering any ntp command. When you use the ntp disable command, the NTP service is activated (if it has not already been activated) and the interface is configured to reject NTP packets simultaneously.
In the no form of any ntp command, all the keywords are optional. However, you must remove all NTP commands from the interface before you can enter the ntp disable command on that interface.
When you enter the no ntp disable command, the interface that was configured to reject NTP packets is enabled to receive NTP packets. The NTP service itself remains active, along with any other functions you previously configured.
To terminate NTP service on a device, you must enter the no ntp command without keywords. For example, if you previously issued the ntp disable command and you now want to remove not only this restriction, but all NTP functions from the device, use the no ntp command without any keywords. This ensures that all NTP functions are removed and that the NTP service is also terminated.
Examples
The following example shows how to prevent Ethernet interface 0 from receiving NTP packets:
Router(config)# interface ethernet 0Router(config-if)# ntp disableThe following example shows the display after trying to execute ntp disable on an interface with other NTP commands configured on it:
Router(config-if)# ntp disable%NTP: Unconfigure other NTP commands on this interface before executing `ntp disable'Router(config-if)#The following example shows how to remove all the configured NTP options and disable the ntp server:
Router(config)# no ntpntp logging
To enable Network Time Protocol (NTP) message logging, use the ntp logging command in global configuration mode. To disable NTP logging, use the no form of this command.
ntp logging
no ntp [logging]
Syntax Description
This command has no arguments or keywords.
Defaults
NTP message logging is disabled.
Command Modes
Global configuration
Command History
Usage Guidelines
Use the ntp logging command to control the display of NTP logging messages.
The NTP service can be activated by entering any ntp command. When you use the ntp logging command, the NTP service is activated (if it has not already been activated) and message logging is enabled simultaneously.
In the no form of any ntp command, all the keywords are optional. When you enter the no ntp logging command, only the message logging is disabled in the NTP service. The NTP service itself remains active, along with any other functions you previously configured.
To terminate NTP service on a device, you must enter the no ntp command without keywords. For example, if you previously issued the ntp logging command and you now want to disable not only the message logging, but all NTP functions from the device, use the no ntp command without any keywords. This ensures that all NTP functions are removed and that the NTP service is also terminated.
Examples
The following example shows how to enable NTP message logging and verify that it is enabled:
Router# configure terminalEnter configuration commands, one per line. End with CNTL/Z.Router(config)# ntp loggingRouter(config)# endRouter# show running-config | include ntpntp loggingntp clock-period 17180152ntp peer 10.0.0.1ntp server 192.168.166.3In the preceding example, the "ntp logging" entry in the configuration file verifies that NTP message logging is enabled.
The following example shows how to disable NTP message logging and verify that it is disabled:
Router# configure terminalEnter configuration commands, one per line. End with CNTL/Z.Router(config)# no ntp loggingRouter# endRouter(config)# show running-config | include ntpntp clock-period 17180152ntp peer 18.0.0.1ntp server 128.107.166.3The "ntp logging" entry no longer appears in the configuration file, which verifies that NTP message logging is disabled.
The following example shows how to remove all the configured NTP options and disable the ntp server:
Router(config)# no ntp
Related Commands
ntp peer
Configures the software clock to synchronize a peer or to be synchronized by a peer.
ntp server
Allows the software clock to be synchronized by an NTP time server.
ntp master
To configure the Cisco IOS software as a Network Time Protocol (NTP) master clock to which peers synchronize themselves when an external NTP source is not available, use the ntp master command in global configuration mode. To disable the master clock function, use the no form of this command.
ntp master [stratum]
no ntp [master]
Caution
Syntax Description
stratum
(Optional) Number from 1 to 15. Indicates the NTP stratum number that the system will claim.
Defaults
By default, the master clock function is disabled. When enabled, the default stratum is 8.
Command Modes
Global configuration
Command History
Usage Guidelines
Because the Cisco implementation of NTP does not support directly attached radio or atomic clocks, the router is normally synchronized, directly or indirectly, to an external system that has such a clock. In a network without Internet connectivity, such a time source may not be available. The ntp master command is used in such cases.
If the system has ntp master configured, and it cannot reach any clock with a lower stratum number, the system will claim to be synchronized at the configured stratum number, and other systems will be willing to synchronize to it via NTP.
Note
The NTP service can be activated by entering any ntp command. When you use the ntp master command, the NTP service is activated (if it has not already been activated) and the Cisco IOS software is configured as an NTP master clock simultaneously.
In the no form of any ntp command, all the keywords are optional. When you enter the no ntp master command, only the NTP master clock configuration is removed from the NTP service. The NTP service itself remains active, along with any other functions you previously configured.
To terminate NTP service on a device, you must enter the no ntp command without keywords. For example, if you previously issued the ntp master command and you now want to remove not only the master clock function, but all NTP functions from the device, use the no ntp command without any keywords. This ensures that all NTP functions are removed and that the NTP service is also terminated.
Examples
The following example shows how to configure a router as an NTP master clock to which peers may synchronize:
Router(config)# ntp master 10The following example shows how to remove all the configured NTP options and disable the ntp server:
Router(config)# no ntpRelated Commands
clock calendar-valid
Configures the system hardware clock an authoritative time source for the network.
ntp max-associations
To configure the maximum number of Network Time Protocol (NTP) peers and clients for a routing device, use the ntp max-associations command in global configuration mode. To return the maximum associations value to the default, use the no form of this command.
ntp max-associations number
no ntp [max-associations]
Syntax Description
Defaults
100 maximum associations.
Command Modes
Global configuration
Command History
Usage Guidelines
The router can be configured to define the maximum number of NTP peer and client associations that the router will serve. The ntp max-associations command is used to set this limit.
For a router, this command is useful for ensuring that the router is not overwhelmed by NTP synchronization requests. For an NTP master server, this command is useful for allowing numerous devices to synchronize to a router.
The NTP service can be activated by entering any ntp command. When you use the ntp max-associations command, the NTP service is activated (if it has not already been activated) and the maximum number of NTP peers and clients is configured simultaneously.
In the no form of any ntp command, all the keywords are optional. When you enter the no ntp max-associations command, only the maximum number value is removed from the NTP service. The NTP service itself remains active, along with any other functions you previously configured.
To terminate NTP service on a device, you must enter the no ntp command without keywords. For example, if you previously issued the ntp max-associations command and you now want to remove not only that maximum value, but all NTP functions from the device, use the no ntp command without any keywords. This ensures that all NTP functions are removed and that the NTP service is also terminated.
Examples
In the following example, the router is configured to act as an NTP server to 200 clients:
Router(config)# ntp max-associations 200The following example shows how to remove all the configured NTP options and disable the ntp server:
Router(config)# no ntpRelated Commands
ntp multicast client
To configure the system to receive Network Time Protocol (NTP) multicast packets on a specified interface, use the ntp multicast client interface configuration command. To disable this capability, use the no form of this command.
ntp multicast client [ip-address]
no ntp [multicast client [ip-address]]
Syntax Description
Defaults
Disabled
Command Modes
Interface configuration
Command History
Usage Guidelines
Use this command to allow the system to listen to multicast packets on an interface-by-interface basis.
The NTP service can be activated by entering any ntp command. When you use the ntp multicast client command, the NTP service is activated (if it has not already been activated) and the interface on which to receive multicast packets is configured simultaneously.
In the no form of any ntp command, all the keywords are optional. When you enter the no ntp multicast client command, only the multicast client capability is removed from the NTP service. The NTP service itself remains active, along with any other functions you previously configured.
To terminate NTP service on a device, you must enter the no ntp command without keywords. For example, if you previously issued the ntp multicast client command and you now want to remove not only the multicast client capability, but all NTP functions from the device, use the no ntp command without any keywords. This ensures that all NTP functions are removed and that the NTP service is also terminated.
Examples
In the following example, the system is configured to receive (listen to) NTP multicast packets on Ethernet interface 1:
Router(config)# interface ethernet 1Router(config-if)# ntp multicast clientThe following example shows how to remove all the configured NTP options and disable the ntp server:
Router(config)# no ntpRelated Commands
ntp multicast
To configure a system to send Network Time Protocol (NTP) multicast packets on a specified interface, use the ntp multicast interface configuration command. To disable this capability, use the no form of this command.
ntp multicast [ip-address] [key key-id] [ttl value] [version number]
no ntp [multicast]
Syntax Description
Defaults
Disabled
Command Modes
Interface configuration
Command History
Usage Guidelines
The TTL value is used to limit the scope of an audience for multicast routing.
The NTP service can be activated by entering any ntp command. When you use the ntp multicast command, the NTP service is activated (if it has not already been activated) and the interface on which to send multicast packets is configured simultaneously.
In the no form of any ntp command, all the keywords are optional. When you enter the no ntp multicast command, only the multicast capability is removed from the NTP service. The NTP service itself remains active, along with any other functions you previously configured.
To terminate NTP service on a device, you must enter the no ntp command without keywords. For example, if you previously issued the ntp multicast command and you now want to remove not only the multicast capability, but all NTP functions from the device, use the no ntp command without any keywords. This ensures that all NTP functions are removed and that the NTP service is also terminated.
Examples
The following example shows how to configure Ethernet interface 0 to send NTP version 2 broadcasts:
Router(config)# interface ethernet 0Router(config-if)# ntp multicast version 2The following example shows how to remove all the configured NTP options and disable the ntp server:
Router(config)# no ntpRelated Commands
ntp authentication-key
Defines an authentication key for NTP.
ntp multicast client
Allows the system to receive NTP multicast packets on an interface.
ntp peer
To configure the software clock to synchronize a peer or to be synchronized by a peer, use the ntp peer command in global configuration mode. To disable this capability, use the no form of this command.
ntp peer {{[vrf vrf-name] ip-address | hostname}[normal-sync][version number] [key key-id] [source interface] [prefer]}
no ntp {[vrf vrf-name] ip-address | hostname}
Syntax Description
Command Default
No peers are configured.
Command Modes
Global configuration
Command History
Usage Guidelines
When a peer is configured, the default NTP version number is 3, no authentication key is used, and the source IP address is taken from the outgoing interface.
Use this command to allow a device to synchronize with a peer, or vice versa. Using the prefer keyword reduces switching between peers.
Tip
The NTP service can be activated by entering any ntp command. When you use the ntp peer command, the NTP service is activated (if it has not already been activated) and the peer is configured simultaneously.
In the no form of any ntp command, all the keywords are optional. When you enter the no ntp peer command, only the NTP peer configuration is removed from NTP service. The NTP service itself remains active, along with any other functions you previously configured.
To terminate NTP service on a device, you must enter the no ntp command without keywords. For example, if you previously issued the ntp peer command and you now want to remove not only the peer, but all NTP functions from the device, use the no ntp command without any keywords. This ensures that all NTP functions are removed and that the NTP service is also terminated.
Examples
The following example shows how to configure a router to allow its software clock to be synchronized with the clock of the peer (or vice versa) at IP address 192.168.22.33 using NTP version 2. The source IP address is the address of Ethernet 0.
Router(config)# ntp peer 192.168.22.33 version 2 source ethernet 0The following example shows how to disable rapid synchronization at startup:
Router(config)# ntp peer 192.168.22.33 normal-syncThe following example shows how to keep a peer configured but re-enable rapid synchronization at startup after previously disabling it:
Router(config)# ntp peer 192.168.22.33The following example shows how to remove all the configured NTP options and disable the ntp server:
Router(config)# no ntpRelated Commands
ntp refclock
To configure an external clock source for use with Network Time Protocol (NTP) services, use the ntp refclock command in line configuration mode. To disable support of the external time source, use the no form of this command.
ntp refclock {trimble | telecom-solutions} pps {cts | ri | none} [inverted] [pps-offset number] [stratum number] [timestamp-offset number]
no ntp [refclock]
Syntax Description
Defaults
This command is disabled by default.
Command Modes
Line configuration (for auxilary 0 only)
Command History
12.1
The trimble keyword was added to provide driver activation for a Trimble GPS time source on the Cisco 7200 series router.
Usage Guidelines
To configure a PPS signal as the source for NTP synchronization, use the following form of the ntp refclock command:
ntp refclock pps {cts | ri} [inverted] [pps-offset number] [stratum number] [timestamp-offset number]
To configure a Trimble Palisade NTP Synchronization Kit as the GPS clock source connected to the auxiliary port of a Cisco 7200 router, use the following form of the ntp refclock command:
ntp refclock trimble pps none [stratum number]
To configure a Telecom Solutions product as the GPS clock source, use the ntp refclock telecom-solutions form of the command:
ntp refclock telecom-solutions pps cts [stratum number]
The NTP service can be activated by entering any ntp command. When you use the ntp refclock command, the NTP service is activated (if it has not already been activated) and the external clock source is configured simultaneously.
In the no form of any ntp command, all the keywords are optional. When you enter the no ntp refclock command, only the external clock source is removed from the NTP service. The NTP service itself remains active, along with any other functions you previously configured.
To terminate NTP service on a device, you must enter the no ntp command without keywords. For example, if you previously issued the ntp refclock command and you now want to remove not only the external clock source, but all NTP functions from the device, use the no ntp command without any keywords. This ensures that all NTP functions are removed and that the NTP service is also terminated.
Examples
The following example shows configuration of a Trimble Palisade GPS time source on a Cisco 7200 router:
Router(config)# ntp masterRouter(config)# ntp update-calendarRouter(config)# line aux 0Router(config-line)# ntp refclock trimble pps noneThe following example shows configuration of a Telecom Solutions GPS time source on a Catalyst switch platform:
Router(config)# ntp masterRouter(config)# ntp update-calendarRouter(config)# line aux 0Router(config-line)# ntp refclock telecom-solutions pps cts stratum 1The following example shows how to remove all the configured NTP options and disable the ntp server:
Router(config)# no ntpRelated Commands
show ntp associations
Displays the status of NTP associations configured for your system.
ntp server
To allow the software clock to be synchronized by a Network Time Protocol (NTP) time server, use the ntp server command in global configuration mode. To disable this capability, use the no form of this command.
ntp server {{[vrf vrf-name] ip-address | hostname} [version number] [key key-id] [source interface] [prefer]}
no ntp server {[vrf vrf-name] ip-address | hostname}
Syntax Description
Defaults
No servers are configured by default. If a server is configured, the default NTP version number is 3, no authentication key is used, and the source IP address is taken from the outgoing interface.
Command Modes
Global configuration
Command History
Usage Guidelines
Use this command if you want to allow the system to synchronize with the specified server. The server will not synchronize to this machine.
When you use the hostname option, the router does a domain name server (DNS) lookup on that name, and stores the IP address in the configuration. For example, if you enter the command ntp server host1 and then check the running configuration, the output shows "ntp server 172.16.0.4," assuming that the router is correctly configured as a DNS client.
Use the prefer keyword if you use this command multiple times, and you want to set a preferred server. Using the prefer keyword reduces switching between servers.
If you are using the default version of 3 and NTP synchronization does not occur, try NTP version 2. Some NTP servers on the Internet run version 2.
The NTP service can be activated by entering any ntp command. When you use the ntp server command, the NTP service is activated (if it has not already been activated) and software clock synchronization is configured simultaneously.
In the no form of any ntp command, all the keywords are optional. When you enter the no ntp server command, only the server synchronization capability is removed from the NTP service. The NTP service itself remains active, along with any other functions you previously configured.
To terminate NTP service on a device, you must enter the no ntp command without keywords. For example, if you previously issued the ntp server command and you now want to remove not only the server synchronization capability, but all NTP functions from the device, use the no ntp command without any keywords. This ensures that all NTP functions are removed and that the NTP service is also terminated.
Examples
The following example shows how to configure a router to allow its software clock to be synchronized with the clock by the device at IP address 172.16.22.44 using NTP version 2:
Router(config)# ntp server 172.16.22.44 version 2The following example shows how to remove all the configured NTP options and disable the ntp server:
Router(config)# no ntpRelated Commands
ntp source
To use a particular source address in Network Time Protocol (NTP) packets, use the ntp source command in global configuration mode. To remove the specified source address, use the no form of this command.
ntp source type number
no ntp [source]
Syntax Description
Defaults
Source address is determined by the outgoing interface.
Command Modes
Global configuration
Command History
Usage Guidelines
Use this command when you want to use a particular source IP address for all NTP packets. The address is taken from the named interface. This command is useful if the address on an interface cannot be used as the destination for reply packets. If the source keyword is present on an ntp server or ntp peer global configuration command, that value overrides the global value set by this command.
The NTP service can be activated by entering any ntp command. When you use the ntp source command, the NTP service is activated (if it has not already been activated) and the source address is configured simultaneously.
In the no form of any ntp command, all the keywords are optional. When you enter the no ntp source command, only the source address is removed from the NTP service. The NTP service itself remains active, along with any other functions you previously configured.
To terminate NTP service on a device, you must enter the no ntp command without keywords. For example, if you previously issued the ntp source command and you now want to remove not only the configured source address, but all NTP functions from the device, use the no ntp command without any keywords. This ensures that all NTP functions are removed and that the NTP service is also terminated.
Examples
The following example shows how to configure a router to use the IP address of Ethernet 0 as the source address of all outgoing NTP packets:
Router(config)# ntp source ethernet 0The following example shows how to remove all the configured NTP options and disable the ntp server:
Router(config)# no ntpRelated Commands
ntp peer
Configures the software clock to synchronize a peer or to be synchronized by a peer.
ntp server
Allows the software clock to be synchronized by a time server.
ntp trusted-key
To authenticate the identity of a system to which Network Time Protocol (NTP) will synchronize, use the ntp trusted-key command in global configuration mode. To disable authentication of the identity of the system, use the no form of this command.
ntp trusted-key key-number
no ntp [trusted-key key-number]
Syntax Description
Defaults
Disabled
Command Modes
Global configuration
Command History
Usage Guidelines
If authentication is enabled, use this command to define one or more key numbers (corresponding to the keys defined with the ntp authentication-key command) that a peer NTP system must provide in its NTP packets, in order for this system to synchronize to it. This function provides protection against accidentally synchronizing the system to a system that is not trusted, because the other system must know the correct authentication key.
The NTP service can be activated by entering any ntp command. When you use the ntp trusted-key command, the NTP service is activated (if it has not already been activated) and the system to which NTP will synchronize is authenticated simultaneously.
In the no form of any ntp command, all the keywords are optional. When you enter the no ntp trusted-key command, only the authentication is disabled in the NTP service. The NTP service itself remains active, along with any other functions you previously configured.
To terminate NTP service on a device, you must enter the no ntp command without keywords. For example, if you previously issued the ntp trusted-key command and you now want to remove not only the authentication, but all NTP functions from the device, use the no ntp command without any keywords. This ensures that all NTP functions are removed and that the NTP service is also terminated.
Examples
The following example shows how to configure the system to synchronize only to systems providing authentication key 42 in its NTP packets:
Router(config)# ntp authenticateRouter(config)# ntp authentication-key 42 md5 aNiceKeyRouter(config)# ntp trusted-key 42The following example shows how to remove all the configured NTP options and disable the ntp server:
Router(config)# no ntpRelated Commands
ntp authenticate
Enables NTP authentication.
ntp authentication-key
Defines an authentication key for NTP.
ntp update-calendar
To periodically update the hardware clock (calendar) from a Network Time Protocol (NTP) time source, use the ntp update-calendar command in global configuration mode. To disable the periodic updates, use the no form of this command.
ntp update-calendar
no ntp [update-calendar]
Syntax Description
This command has no arguments or keywords.
Defaults
The hardware clock (calendar) is not updated.
Command Modes
Global configuration
Command History
Usage Guidelines
Some platforms have a battery-powered hardware clock, referred to in the command-line interface (CLI) as the "calendar," in addition to the software based system clock. The hardware clock runs continuously, even if the router is powered off or rebooted.
If the software clock is synchronized to an outside time source via NTP, it is a good practice to periodically update the hardware clock with the time learned from NTP. Otherwise, the hardware clock will tend to gradually lose or gain time (drift), and the software clock and hardware clock may become out of synchronization with each other. The ntp update-calendar command will enable the hardware clock to be periodically updated with the time specified by the NTP source. The hardware clock will be updated only if NTP has synchronized to an authoritative time server.
Many lower-end routers (for example, the Cisco 2500 series or the Cisco 2600 series) do not have hardware clocks, so this command is not available on those platforms.
To force a single update of the hardware clock from the software clock, use the clock update-calendar EXEC command.
The NTP service can be activated by entering any ntp command. When you use the ntp update-calendar command, the NTP service is activated (if it has not already been activated) and the hardware clock is updated simultaneously.
In the no form of any ntp command, all the keywords are optional. When you enter the no ntp update-calendar command, only the clock updates are stopped in the NTP service. The NTP service itself remains active, along with any other functions you previously configured.
To terminate NTP service on a device, you must enter the no ntp command without keywords. For example, if you previously issued the ntp update-calendar command and you now want to disable not only the periodic updates, but all NTP functions running on the device, use the no ntp command without any keywords. This ensures that all NTP functions are removed and that the NTP service is also terminated.
Examples
The following example shows how to configure the system to periodically update the hardware clock from the NTP time source:
Router(config)# ntp update-calendarThe following example shows how to remove all the configured NTP options and disable the ntp server:
Router(config)# no ntpRelated Commands
parser cache
To reenable the Cisco IOS software parser cache after disabling it, use the parser cache command in global configuration mode. To disable the parser cache, use the no form of this command.
parser cache
no parser cache
Syntax Description
This command has no arguments or keywords.
Defaults
Parser cache is enabled by default.
Command Modes
Global configuration
Command History
Usage Guidelines
The Parser Cache feature optimizes the parsing (translation and execution) of Cisco IOS software configuration command lines by remembering how to parse recently encountered command lines, decreasing the time required to process large configuration files.
The parser cache is enabled by default. However, if you wish to disable the parser cache, you may do so using the no parser cache command in global configuration mode. To reenable the parser cache after it has been disabled, use the parser cache command.
When the no parser cache is issued, the command line appears in the running configuration file. However, if the parser cache is reenabled, no command line appears in the running configuration file.
Examples
In the following example, the Cisco IOS software Parser Cache feature is disabled:
Router(config)# no parser cacheRelated Commands
partition
To separate Flash memory into partitions on Class B file system platforms, use the partition command in global configuration mode. To undo partitioning and to restore Flash memory to one partition, use the no form of this command.
Cisco 1600 Series and Cisco 3600 Series Routers
partition flash-filesystem: [number-of-partitions][partition-size]
no partition flash-filesystem:
All Other Class B Platforms
partition flash partitions [size1 size2]
no partition flash
Syntax Description
Defaults
Flash memory consists of one partition.
If the partition size is not specified, partitions of equal size are created.
Command Modes
Global configuration
Command History
Usage Guidelines
For the Cisco 1600 series and Cisco 3600 series routers, to undo partitioning, use the partition flash-filesystem:1 or no partition flash-filesystem: command. For other Class B platforms, use either the partition flash 1 or no partition flash command. If there are files in a partition other than the first, you must use the erase flash-filesystem:partition-number command to erase the partition before reverting to a single partition.
When creating two partitions, you must not truncate a file or cause a file to spill over into the second partition.
Examples
The following example creates two partitions of 4 MB each in Flash memory:
Router(config)# partition flash 2 4 4The following example divides the Flash memory card in slot 0 into two partitions, each 8 MB in size on a Cisco 3600 series router:
Router(config)# partition slot0: 2 8 8The following example creates four partitions of equal size in the card on a Cisco 1600 series router:
Router(config)# partition flash: 4paths-of-statistics-kept
To set the number of paths for which statistics are maintained per hour for the Service Assurance Agent (SAA) operation, use the paths-of-statistics-kept command in SAA RTR configuration mode. To return to the default value, use the no form of this command.
paths-of-statistics-kept size
no paths-of-statistics-kept
Syntax Description
size
Number of paths for which statistics are maintained per hour. The default is 5 paths for type pathEcho and 1 path for type echo.
Defaults
5 paths for type pathEcho
1 path for type echo
Command Modes
SAA RTR configuration
Command History
Usage Guidelines
A path is the route the request packet of the operation takes through the network to get to its destination. The operation may take a different path to reach its destination for each SAA operation.
When the number of paths reaches the size specified, no further path information is stored.
Examples
The following example maintains statistics for only 3 paths for operation 2:
Router(config)# rtr 2Router(config-rtr)# type pathEcho protocol ipIcmpEcho 172.16.1.177Router(config-rtr)# paths-of-statistics-kept 3Related Commands
periodic
To specify a recurring (weekly) time range for functions that support the time-range feature, use the periodic command in time-range configuration mode. To remove the time limitation, use the no form of this command.
periodic days-of-the-week hh:mm to [days-of-the-week] hh:mm
no periodic days-of-the-week hh:mm to [days-of-the-week] hh:mm
Syntax Description
Defaults
No recurring time range is defined.
Command Modes
Time-range configuration (config-time-range)
Command History
Usage Guidelines
For Cisco IOS Release 12.2(11)T, IP and Internetwork Packet Exchange (IPX) extended access lists are the only functions that can use time ranges. For further information on using these functions, refer to the Cisco IOS IP Configuration Guide and the Cisco IOS AppleTalk and Novell IPX Configuration Guide.
The periodic command is one way to specify when a time range is in effect. Another way is to specify an absolute time period with the absolute command. Use either of these commands after the time-range global configuration command, which specifies the name of the time range. Multiple periodic entries are allowed per time-range command.
If the end days-of-the-week value is the same as the start value, they can be omitted.
If a time-range command has both absolute and periodic values specified, then the periodic items are evaluated only after the absolute start time is reached, and are not further evaluated after the absolute end time is reached.
Note
Table 36 lists some typical settings for your convenience:
Examples
The following example configuration denies HTTP traffic on Monday through Friday from 8:00 a.m. to 6:00 p.m.:
Router# show startup-config...time-range no-httpperiodic weekdays 8:00 to 18:00!ip access-list extended strictdeny tcp any any eq http time-range no-http!interface ethernet 0ip access-group strict in...The following example configuration permits Telnet traffic on Mondays, Tuesdays, and Fridays from 9:00 a.m. to 5:00 p.m.:
Router# show startup-config
...time-range testingperiodic Monday Tuesday Friday 9:00 to 17:00!ip access-list extended legalpermit tcp any any eq telnet time-range testing!interface ethernet 0ip access-group legal in...Related Commands
