Configuring ntp access restrictions – Dell POWEREDGE M1000E User Manual

Page 184

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7-8

Cisco Catalyst Blade Switch 3130 and 3032 for Dell Software Configuration Guide

OL-13270-03

Chapter 7 Administering the Switch

Managing the System Time and Date

To disable an interface from receiving NTP broadcast packets, use the no ntp broadcast client interface
configuration command. To change the estimated round-trip delay to the default, use the no ntp
broadcastdelay
global configuration command.

This example shows how to configure a port to receive NTP broadcast packets:

Switch(config)# interface gigabitethernet1/0/1

Switch(config-if)# ntp broadcast client

Configuring NTP Access Restrictions

You can control NTP access on two levels as described in these sections:

Creating an Access Group and Assigning a Basic IP Access List, page 7-8

Disabling NTP Services on a Specific Interface, page 7-10

Creating an Access Group and Assigning a Basic IP Access List

Beginning in privileged EXEC mode, follow these steps to control access to NTP services by using
access lists:

Step 5

ntp broadcastdelay microseconds

(Optional) Change the estimated round-trip delay between the switch and
the NTP broadcast server.

The default is 3000 microseconds; the range is 1 to 999999.

Step 6

end

Return to privileged EXEC mode.

Step 7

show running-config

Verify your entries.

Step 8

copy running-config startup-config

(Optional) Save your entries in the configuration file.

Command

Purpose

Command

Purpose

Step 1

configure terminal

Enter global configuration mode.

Step 2

ntp access-group {query-only |
serve-only | serve | peer}
access-list-number

Create an access group, and apply a basic IP access list.

The keywords have these meanings:

query-only—Allows only NTP control queries.

serve-only—Allows only time requests.

serve—Allows time requests and NTP control queries, but does not
allow the switch to synchronize to the remote device.

peer—Allows time requests and NTP control queries and allows the
switch to synchronize to the remote device.

For access-list-number, enter a standard IP access list number from 1
to 99.

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