Specifications

4-12
System Management Software Configuration Guide for Cisco IE 2000U and Connected Grid Switches
Chapter 4 Administering the Switch
Configuring NTP
• Disabling NTP Services on a Specific Interface, page 4-13
Creating an Access Group and Assigning a Basic IP Access List
The access group keywords are scanned in this order, from least restrictive to most restrictive:
1. peer—Allows time requests and NTP control queries and allows the switch to synchronize itself to
a device whose address passes the access list criteria.
2. serve—Allows time requests and NTP control queries, but does not allow the switch to synchronize
itself to a device whose address passes the access list criteria.
3. serve-only—Allows only time requests from a device whose address passes the access list criteria.
4. query-only—Allows only NTP control queries from a device whose address passes the access list
criteria.
If the source IP address matches the access lists for more than one access type, the first type is granted.
If no access groups are specified, all access types are granted to all devices. If any access groups are
specified, only the specified access types are granted.
BEFORE YOU BEGIN
Review the “Network Time Protocol” section on page 4-2.
DETAILED STEPS
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.