Configuring Ntp Access Restrictions - Cisco C3201FESMIC-TP= - 3201 Fast EN Switch Mobile Interface Card Expansion Module Software Configuration Manual

Managing the System Time and Date

Configuring NTP Access Restrictions

You can control NTP access by using access lists.
Creating an Access Group and Assigning a Basic IP Access List
To control access to NTP services by using access lists, follow these steps, beginning in privileged EXEC
mode:
Command
Step 1 configure terminal
Step 2 ntp access-group {query-only |
serve-only | serve | peer}
access-list-number
Step 3 access-list access-list-number permit
source [source-wildcard]
Step 4 end
Step 5 show running-config
Step 6 copy running-config startup-config
The access group keywords are scanned in this order, from least restrictive to most restrictive:
1.
2.
Cisco 3200 Series Wireless MIC Software Configuration Guide
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Purpose
Enters global configuration mode.
Creates an access group, and applies a basic IP access list.
The keywords have these meanings:
For access-list-number, enter a standard IP access list number from 1
to 99.
Creates the access list.
Note
Returns to privileged EXEC mode.
Verifies your entries.
(Optional) Saves your entries in the configuration file.
peer—Allows time requests and NTP control queries and allows the WMIC to synchronize itself to
a device whose address passes the access list criteria.
serve—Allows time requests and NTP control queries, but does not allow the WMIC to synchronize
itself to a device whose address passes the access list criteria.
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 WMIC to synchronize to the remote device.
peer—Allows time requests and NTP control queries and allows the
•
WMIC to synchronize to the remote device.
For access-list-number, enter the number specified in Step 2.
•
• Enter the permit keyword to permit access if the conditions are
matched.
For source, enter the IP address of the device that is permitted access
•
to the WMIC.
(Optional) For source-wildcard, enter the wildcard bits to be applied
•
to the source.
When creating an access list, remember that, by default, the end
of the access list contains an implicit deny statement for
everything if it did not find a match before reaching the end.
Administering the WMIC