Cisco IOS Configuration Fundamentals Command Reference
Basic System Management Commands
Basic System Management Commands
Basic system management tasks include naming the router, enabling basic services, and configuring the Network Time Protocol (NTP).
absolute
Syntax Description
Defaults
Command Modes
Examples
Related Commands
alias
Syntax Description
Defaults
absolute
To specify an absolute time when a time range is in effect, use the absolute time-range configuration command. To remove the time limitation, use the no form of this command.
absolute [start time date] [end time date]
no absolute
absolute [start time date] [end time date]
no absolute
Syntax Description
start time date: (Optional) Absolute time and date that the associated permit or deny statement starts going into effect. The time is expressed in a 24-hour clock, in the form of hours:minutes. For example, 8:00 is 8:00 am and 20:00 is 8:00 pm. The date is expressed in the format day month year. The minimum start is 00:00 1 January 1993. If no start time and date are specified, the permit or deny statement is in effect immediately
end time date: (Optional) Absolute time and date that the associated permit or deny statement is no longer in effect. Same time and date format as described for the start. The end time and date must be after the start time and date. The maximum end time is 23:59 31 December 2035. If no end time and date are specified, the permit or deny statement is in effect indefinitely.
end time date: (Optional) Absolute time and date that the associated permit or deny statement is no longer in effect. Same time and date format as described for the start. The end time and date must be after the start time and date. The maximum end time is 23:59 31 December 2035. If no end time and date are specified, the permit or deny statement is in effect indefinitely.
Defaults
There is no absolute time when the time range is in effect.
Command Modes
Time-range configuration
Examples
The following example configures an access list named northeast, which references a time range named xyz. The access list and time range together permit traffic on Ethernet interface 0 starting at noon on January 1, 2001 and going forever.
time-range xyz
absolute start 12:00 1 January 2001
!
ip access-list extended northeast
permit ip any any time-range xyz
!
interface ethernet 0
ip access-group northeast in
The following example permits UDP traffic until noon on December 31, 2000. After that time, UDP
traffic is no longer allowed out Ethernet interface 0.
time-range abc
absolute end 12:00 31 December 2000
!
ip access-list extended northeast
permit udp any any time-range abc
!
interface ethernet 0
ip access-group northeast out
The following example permits UDP traffic out Ethernet interface 0 on weekends only, from 8:00 a.m.
on January 1, 1999 to 6:00 p.m. on December 31, 2001:
time-range test
absolute start 8:00 1 January 1999 end 18:00 31 December 2001
periodic weekends 00:00 to 23:59
!
ip access-list extended northeast
permit udp any any time-range test
!
interface ethernet 0
ip access-group northeast out
time-range xyz
absolute start 12:00 1 January 2001
!
ip access-list extended northeast
permit ip any any time-range xyz
!
interface ethernet 0
ip access-group northeast in
The following example permits UDP traffic until noon on December 31, 2000. After that time, UDP
traffic is no longer allowed out Ethernet interface 0.
time-range abc
absolute end 12:00 31 December 2000
!
ip access-list extended northeast
permit udp any any time-range abc
!
interface ethernet 0
ip access-group northeast out
The following example permits UDP traffic out Ethernet interface 0 on weekends only, from 8:00 a.m.
on January 1, 1999 to 6:00 p.m. on December 31, 2001:
time-range test
absolute start 8:00 1 January 1999 end 18:00 31 December 2001
periodic weekends 00:00 to 23:59
!
ip access-list extended northeast
permit udp any any time-range test
!
interface ethernet 0
ip access-group northeast out
Related Commands
deny : Sets conditions under which a packet does not pass a named access list.
periodic: Specifies a recurring (weekly) start and end time for a time-range.
permit: Sets conditions under which a packet passes a named access list.
time-range: Enables time-range configuration mode and names a time-range definition.
periodic: Specifies a recurring (weekly) start and end time for a time-range.
permit: Sets conditions under which a packet passes a named access list.
time-range: Enables time-range configuration mode and names a time-range definition.
alias
To create a command alias, use the alias global configuration command. Use the no form of this command to delete all aliases in a command mode or to delete a specific alias, and to revert to the original command syntax.
alias mode alias-name alias-command-line
no alias mode [alias-name]
alias mode alias-name alias-command-line
no alias mode [alias-name]
Syntax Description
mode Command mode of the original and alias commands.
alias-name Command alias.
alias-command-line Original command syntax.
alias-name Command alias.
alias-command-line Original command syntax.
Defaults
Default aliases are in EXEC mode as follows:
| Command Alias | Original Command |
| h | help |
| lo | ping |
| r | resume |
| s | show |
| w | where |
| Argument options | mode |
| configuration | Global configuration |
| controller | Controller configuration |
| exec | EXEC |
| hub | Hub configuration |
| interface | Interface configuration |
| ipx-router | IPX router configuration |
| line | Line configuration |
| map-class | Map class configuration |
| map-list | Map list configuration |
| route-map | Route map configuration |
| router | Router configuration |
When you use online help, command aliases are indicated by an asterisk (*), as follows:
Router#lo?
*lo=logout lock login logout
When you use online help, aliases that contain spaces (for example, telnet device.cisco.com 25) are
displayed as follows:
Router# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)# alias exec device-mail telnet device.cisco.com 25
Router(config)# end
Router# device-mail?
*device-mail=”telnet device.cisco.com 25"
When you use online help, the alias is expanded and replaced with the original command, as shown in
the following example with the td alias:
Router(config)# alias exec td trace device
Router(config)# ^Z
Router# t?
*td=”trace device” telnet terminal test tn3270
trace
To list only commands and omit aliases, begin your input line with a space. In the following example,
the alias td is not shown, because there is a space before the t? command line.
Router# t?
telnet terminal test tn3270 trace
As with commands, you can use online help to display the arguments and keywords that can follow a command alias. In the following example, the alias td is created to represent the command telnet device. The /debug and /line switches can be added to telnet device to modify the command:
Router(config)# alias exec td telnet device
Router(config)# ^Z
Router# td ?
/debug Enable telnet debugging mode
/line Enable telnet line mode
...
whois Whois port
Router# telnet device
You must enter the complete syntax for the alias command. Partial syntax for aliases are not accepted. In the following example, the parser does not recognize the command t as indicating the alias td.
Router# t
% Ambiguous command: “t”
Examples
The following example creates the alias fixmyrt for the IP route198.92.116.16: alias exec fixmyrt clear ip route 198.92.116.16
Related Commands
show aliases Displays all alias commands.
buffers
To make adjustments to initial buffer pool settings and to the limits at which temporary buffers are created and destroyed, use the buffers global configuration command. Use the no form of this command to return the buffers to their default size.
buffers {small | middle | big | verybig | large | huge | type number} {permanent | max-free | min-free | initial} number
no buffers {small | middle | big | verybig | large | huge | type number} {permanent | max-free | min-free | initial} number
buffers {small | middle | big | verybig | large | huge | type number} {permanent | max-free | min-free | initial} number
no buffers {small | middle | big | verybig | large | huge | type number} {permanent | max-free | min-free | initial} number
Defaults
The default number of buffers in a pool is determined by the hardware configuration and can displayed with the EXEC show buffers command.
Examples
Examples of Public Buffer Pool Tuning
The following example keeps at least 50 small buffers free in the system:
buffers small min-free 50
The following example increases the permanent buffer pool allocation for big buffers to 200:
buffers big permanent 200
Example of Interface Buffer Pool Tuning
A general guideline is to display buffers with the show buffers command, observe which buffer pool is
depleted, and increase that one.
The following example increases the permanent Ethernet 0 interface buffer pool on a Cisco 4000 is 96
because the Ethernet 0 buffer pool is depleted:
buffers ethernet 0 permanent 96
The following example keeps at least 50 small buffers free in the system:
buffers small min-free 50
The following example increases the permanent buffer pool allocation for big buffers to 200:
buffers big permanent 200
Example of Interface Buffer Pool Tuning
A general guideline is to display buffers with the show buffers command, observe which buffer pool is
depleted, and increase that one.
The following example increases the permanent Ethernet 0 interface buffer pool on a Cisco 4000 is 96
because the Ethernet 0 buffer pool is depleted:
buffers ethernet 0 permanent 96
Related Commands
load-interval Changes the length of time for which data is used to compute load statistics.
show buffers Displays statistics for the buffer pools on the network server.
show buffers Displays statistics for the buffer pools on the network server.
buffers huge size
To dynamically resize all huge buffers to the value you specify, use the buffers huge size global configuration command. Use the no form of this command to restore the default buffer values.
buffers huge size number
no buffers huge size number
buffers huge size number
no buffers huge size number
Defaults
18024 bytes
Command Modes
Global configuration
Examples
The following example resizes huge buffers to 20000 bytes: buffers huge size 20000
Related Commands
buffers Makes adjstmts to initial bufr. pool settings and to the limits at which tmpry buffers are created and destroyed.
show buffers Displays statistics for the buffer pools on the network server.
show buffers Displays statistics for the buffer pools on the network server.
calendar set
To set the system calendar, use one of the formats of the calendar set EXEC command.
calendar set hh:mm:ss day month year
calendar set hh:mm:ss month day year
calendar set hh:mm:ss day month year
calendar set hh:mm:ss month day year
Command Modes
EXEC
Examples
The following example manually sets the system calendar to 1:32 p.m. on July 23, 1997: calendar set 13:32:00 23 July 1997
Related Commands
clock read-calendar Manually reads the calendar into the system clock.
clock set Manually set the system clock.
clock summer-time Configures the system to automatically switch to summer time (daylight savings time).
clock timezone Sets the time zone for display purposes.
clock update-calendar Sets the calendar from the system clock.
clock set Manually set the system clock.
clock summer-time Configures the system to automatically switch to summer time (daylight savings time).
clock timezone Sets the time zone for display purposes.
clock update-calendar Sets the calendar from the system clock.
clock calendar-valid
To configure a router as a time source for a network based on its calendar, use the clock calendar-valid global configuration command. Use the no form of this command to specify that the calendar is not an authoritative time source.
clock calendar-valid
no clock calendar-valid
clock calendar-valid
no clock calendar-valid
Defaults
The router is not configured as a time source.
Examples
The following example configures a router as the time source for a network based on its calendar: clock calendar-valid
Related Commands
ntp master ,vines time use-system
clock read-calendar
To manually read the calendar into the system clock, use the clock read-calendar EXEC command.
clock read-calendar
clock read-calendar
Command Modes
EXEC
Examples
The following example configures the system clock to set its date and time by the calendar setting: clock read-calendar
Related Commands
calendar set,clock set,clock,update-calendar,ntp update-calendar
clock set
To manually set the system clock, use one of the formats of the clock set command in privileged EXEC mode.
clock set hh:mm:ss day month year
clock set hh:mm:ss month day year
clock set hh:mm:ss day month year
clock set hh:mm:ss month day year
Command Modes
Privileged EXEC mode
Examples
The following example manually sets the system clock to 1:32 p.m. on July 23, 1997: clock set 13:32:00 23 July 1997
Related Commands
calendar set,clock read-calendar,clock summer-time,clock timezone
clock summer-time
To configure the system to automatically switch to summer time (daylight savings time), use one of the formats of the clock summer-time global configuration command. Use the no form of this command to configure the Cisco IOS software not to automatically switch to summer time.
clock summer-time zone recurring [week day month hh:mm week day month hh:mm [offset]]
clock summer-time zone date date month year hh:mm date month year hh:mm [offset]
clock summer-time zone date month date year hh:mm month date year hh:mm [offset]
no clock summer-time
clock summer-time zone recurring [week day month hh:mm week day month hh:mm [offset]]
clock summer-time zone date date month year hh:mm date month year hh:mm [offset]
clock summer-time zone date month date year hh:mm month date year hh:mm [offset]
no clock summer-time
Syntax Description
zone Name of the time zone (for example, “PDT” for Pacific Daylight Time) to be displayed when summer time is in effect.
recurring Indicates that summer time should start and end on the corresponding specified days every year.
date Indicates that summer time should start on the first specific date listed in the command and end on the second specific date in the command.
week (Optional) Week of the month (1 to 5 or last).
day (Optional) Day of the week (Sunday, Monday,...).
date Date of the month (1 to 31).
month (Optional) Month (January, February,...).
year Year (1993 to 2035).
hh:mm (Optional) Time (military format) in hours and minutes.
offset (Optional) Number of minutes to add during summer time (default is 60).
recurring Indicates that summer time should start and end on the corresponding specified days every year.
date Indicates that summer time should start on the first specific date listed in the command and end on the second specific date in the command.
week (Optional) Week of the month (1 to 5 or last).
day (Optional) Day of the week (Sunday, Monday,...).
date Date of the month (1 to 31).
month (Optional) Month (January, February,...).
year Year (1993 to 2035).
hh:mm (Optional) Time (military format) in hours and minutes.
offset (Optional) Number of minutes to add during summer time (default is 60).
Defaults
Summer time is disabled. If clock summer-time zone recurring is specified without parameters, the summer time rules default to United States rules. Default of offset is 60.
Examples
The following example specifies that summer time starts on the first Sunday in April at 02:00 and ends
on the last Sunday in October at 02:00:
clock summer-time PDT recurring 1 Sunday April 2:00 last Sunday October 2:00
If you live in a place where summer time does not follow the pattern in the first example, you could set it to start on October 12, 1997 at 02:00, and end on April 26, 1998 at 02:00, with the following example:
clock summer-time date 12 October 1997 2:00 26 April 1998 2:00
on the last Sunday in October at 02:00:
clock summer-time PDT recurring 1 Sunday April 2:00 last Sunday October 2:00
If you live in a place where summer time does not follow the pattern in the first example, you could set it to start on October 12, 1997 at 02:00, and end on April 26, 1998 at 02:00, with the following example:
clock summer-time date 12 October 1997 2:00 26 April 1998 2:00
Related Commands
calendar set, clock timezone
clock timezone
To set the time zone for display purposes, use the clock timezone global configuration command. To set the time to Coordinated Universal Time (UTC), use the no form of this command. clock timezone zone hours- offset [minutes-offset]
no clock timezone
no clock timezone
Syntax Description
zone Name of the time zone to be displayed when standard time is in effect.
hours-offset Hours difference from UTC.
minutes-offset (Optional) Minutes difference from UTC.
hours-offset Hours difference from UTC.
minutes-offset (Optional) Minutes difference from UTC.
Defaults
UTC
Command Modes
Global configuration
clock update-calendar
To set the calendar from the system clock, use the clock update-calendar EXEC command.
clock update-calendar
clock update-calendar
Syntax Description
This command has no arguments or keywords.
Command Modes
EXEC
downward-compatible-config
To generate a configuration that is compatible with an earlier Cisco IOS release, use the downward-compatible-config global configuration command. To remove this feature, use the no form of this command.
downward-compatible-config version
no downward-compatible-config
downward-compatible-config version
no downward-compatible-config
Command Modes
Global configuration
Examples
downward-compatible-config 10.2
hostname
To specify or modify the host name for the network server, use the hostname global configuration command. The host name is used in prompts and default configuration filenames. The setup command facility also prompts for a host name at startup.
hostname name
hostname name
Syntax Description
name New host name for the network server.
Defaults
The factory-assigned default host name is router.
Examples
hostname sandbox
ip bootp server
To access the BOOTP service available from hosts on the network, use the ip bootp server global configuration command. Use the no form of the command to disable these services.
ip bootp server
no ip bootp server
ip bootp server
no ip bootp server
Examples
In the following example, BOOTP and DHCP services are disabled on the router:
Router(config)# no ip bootp server
Router(config)# no service dhcp
Router(config)# no ip bootp server
Router(config)# no service dhcp
Related Commands
service dhcp : Enables the integrated Dynamic Host Configuration Protocol (DHCP) server and relay agent.
ip finger
To configure a system to accept Finger protocol requests (defined in RFC 742), use the ip finger global configuration command. To disable this service, use the no form of this command.
ip finger [rfc-compliant]
no ip finger
ip finger [rfc-compliant]
no ip finger
Syntax Description
rfc-compliant (Optional) Configures the system to wait for “Return” or “/W” input when processing Finger requests. This keyword should not be used for those systems.
Examples
This example disables the Finger protocol: Router(config)# no ip finger
ip telnet source-interface
To allow a user to select an address of an interface as the source address for Telnet connections, use the ip telnet source-interface global configuration command. Use the no form of this command to reset the source address to the default for each connection.
ip telnet source-interface interface
no ip telnet source-interface
ip telnet source-interface interface
no ip telnet source-interface
Syntax Description:
interface The interface whose address is to be used as the source for Telnet connections.
Defaults
The address of the closest interface to the destination as the source address. If the selected interface is not “up,” the Cisco IOS software selects the address of the closest interface to the destination as the source address.
Examples
The following example makes the IP address for Ethernet interface 1 as the source address for Telnet
connections: ip telnet source-interface e 1
connections: ip telnet source-interface e 1
Related Commands
ip radius : Forces RADIUS to use the IP address of a specified interface for all
source-interface : outgoing RADIUS packets.
source-interface : outgoing RADIUS packets.
ip tftp source-interface
To allow a user to select the interface whose address will be used as the source address for TFTP connections, use the ip tftp source-interface global configuration command.
ip tftp source-interface interface
no ip tftp source-interface
ip tftp source-interface interface
no ip tftp source-interface
Syntax Description
interface The interface whose address is to be used as the source for TFTP connections.
Defaults
The address of the closest interface to the destination as the source address. If the selected interface is not “up,”the Cisco IOS software selects the address of the closest interface to the destination as the source address.ExamplesThe following example makes the IP address for Ethernet interface 1 as the source address for TFTP connections: ip tftp source-interface e 1
Related Commands
ip radius : Forces RADIUS to use the IP address of a specified interface for all
source-interface : outgoing RADIUS packets.
source-interface : outgoing RADIUS packets.
load-interval
To change the length of time for which data is used to compute load statistics, use the load-interval interface configuration command. Use the no form of this command to revert to the default setting.
load-interval seconds
no load-interval seconds
load-interval seconds
no load-interval seconds
Syntax Description
seconds Length of time for which data is used to compute load statistics. A value that is a multiple of 30, from 30 to 600 (30, 60, 90, 120, and so forth).
Defaults
300 seconds (or 5 minutes)
Command Modes
Interface configuration
Examples
In the following example, the default 5-minute average is set it to a 30-second average. A burst in traffic that would not trigger a dial backup for an interface configured with the default 5-minute interval might trigger a dial backup for this interface that is set for a shorter, 30-second interval. interface serial 0 : load-interval 30
Related Commands
show interfaces Displays ALC information.
ntp access-group
To control access to the system’s Network Time Protocol (NTP) services, use the ntp access-group global configuration command. To remove access control to the system’s NTP services, use the no form of this command.
ntp access-group {query-only | serve-only | serve | peer} access-list-numberno
ntp access-group {query-only | serve-only | serve | peer}
ntp access-group {query-only | serve-only | serve | peer} access-list-numberno
ntp access-group {query-only | serve-only | serve | peer}
Syntax Description
| query-only | Allows only NTP control queries. See RFC 1305 (NTP version 3) |
| serve-only | Allows only time requests |
| serve | Allows time requests and NTP control queries, but does not allow the system to synchronize to the remote system |
| peer | Allows time requests and NTP control queries and allows the system to synchronize to the remote system |
| access-list-number | Number (1 to 99) of a standard IP access list |
Defaults
No access control (full access granted to all systems)
Examples
The following example configures the 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.
ntp access-group peer 99
ntp access-group serve-only 42
ntp access-group peer 99
ntp access-group serve-only 42
Related 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 global configuration command. Use the no form of this command to disable the feature.
ntp authenticate
no ntp authenticate
ntp authenticate
no ntp authenticate
Examples
The following example configures the system to synchronize only to systems providing authentication key 42 in its NTP packets:
ntp authenticate
ntp authentication-key 42 md5 aNiceKey
ntp trusted-key 42
ntp authenticate
ntp authentication-key 42 md5 aNiceKey
ntp trusted-key 42
Related 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 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 global configuration command. Use the no form of this command to remove the authentication key for NTP.
ntp authentication-key number md5 value
no ntp authentication-key number
ntp authentication-key number md5 value
no ntp authentication-key number
Syntax Description
number : Key number (1 to 4294967295).
value : Key value (an arbitrary string of up to eight characters).
md5 : Authentication key. Message authentication support is provided using the message digest algorithm 5(MD5) algorithm. The key type md5 is currently the only key type supported.
value : Key value (an arbitrary string of up to eight characters).
md5 : Authentication key. Message authentication support is provided using the message digest algorithm 5(MD5) algorithm. The key type md5 is currently the only key type supported.
Examples
The following example configures the system to synchronize only to systems providing authentication
key 42 in its NTP packets:
ntp authenticate
ntp authentication-key 42 md5 aNiceKey
ntp trusted-key 42
key 42 in its NTP packets:
ntp authenticate
ntp authentication-key 42 md5 aNiceKey
ntp trusted-key 42
Related Commands
ntp authenticate : Enables NTP authentication.
ntp peer : Configures the system clock to synchronize a peer or to be synchronized by a peer.
ntp server : Allows the system clock to be synchronized by a time server.
ntp trusted-key : Authenticates the identity of a system to which NTP will synchronize.
ntp peer : Configures the system clock to synchronize a peer or to be synchronized by a peer.
ntp server : Allows the system clock to be synchronized by a time server.
ntp trusted-key : Authenticates the identity of a system to which NTP will synchronize.
ntp broadcast
To specify that a specific interface should send Network Time Protocol (NTP) broadcast packets, use the ntp broadcast interface configuration command. Use the no form of this command to disable this capability.
ntp broadcast [version number]
no ntp broadcast
ntp broadcast [version number]
no ntp broadcast
Syntax Description
version number (Optional) Number from 1 to 3 indicating the NTP version.
Defaults
Disabled
Command Modes
Interface configuration
Examples
The following example configures Ethernet interface 0 to send NTP version 2 packets:
interface ethernet 0
ntp broadcast version 2
interface ethernet 0
ntp broadcast version 2
Related Commands
ntp broadcast client : Allows the system to receive NTP broadcast packets on an interface.
ntp broadcastdelay : Sets the estimated round-trip delay between the Cisco IOS software and an NTP broadcast server.
ntp broadcastdelay : Sets the estimated round-trip delay between the Cisco IOS software and an NTP broadcast server.
ntp broadcast client
To allow the system to receive Network Time Protocol (NTP) broadcast packets on an interface, use the ntp broadcast client interface configuration command. Use the no form of this command to disable this capability.
ntp broadcast client
no ntp broadcast client
ntp broadcast client
no ntp broadcast client
Defaults
Disabled
Command Modes
Interface configuration
Examples
The following example synchronizes the Cisco IOS software to NTP packets broadcast on Ethernet interface 1:
interface ethernet 1
ntp broadcast client
interface ethernet 1
ntp broadcast client
Related Commands
ntp broadcast : Specifies that a specific interface should send NTP broadcast packets.
ntp broadcastdelay : Sets the estimated round-trip delay between the Cisco IOS software and an NTP broadcast server.
ntp broadcastdelay : Sets the estimated round-trip delay between the Cisco IOS software and an NTP broadcast server.
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 global configuration command. Use the no form of this command to revert to the default value.
ntp broadcastdelay microseconds
no ntp broadcastdelay
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
Examples
The following example sets the estimated round-trip delay between a router and the broadcast client to 5000 microseconds: ntp broadcastdelay 5000
Related Commands
ntp broadcast : Specifies that a specific interface should send NTP broadcast packets.
ntp broadcast client : Allows the system to receive NTP broadcast packets on an interface.
ntp broadcast client : Allows the system to receive NTP broadcast packets on an interface.
ntp clock-period
As NTP compensates for the error in the system clock, it keeps track of the correction factor for this error. The system automatically saves this value into the system configuration using the ntp clock-period global configuration command. The system uses the no form of this command to revert to the default.
ntp clock-period value
no ntp clock-period
ntp clock-period value
no ntp clock-period
Syntax Description
value Amount to add to the system clock for each clock hardware tick (in units of 2 to 32 seconds).
Defaults
17179869 2-32 seconds (4 milliseconds)
ntp disable
To prevent an interface from receiving Network Time Protocol (NTP) packets, use the ntp disable interface configuration command. To enable receipt of NTP packets on an interface, use the no form of this command.
ntp disable
no ntp disable
ntp disable
no ntp disable
Command Modes
Interface configuration
Examples
The following example prevents Ethernet interface 0 from receiving NTP packets:
interface ethernet 0 ntp disable
interface ethernet 0 ntp disable
