Cisco Catalyst 4500 series Administration Manual page 177

Chapter 4 Administering the Switch
Creating an Access Group and Assigning a Basic IP Access List
To control access to NTP services by using access lists, perform this task:
Command
Step 1
configure terminal
Step 2
ntp access-group
y |
serve-onl serve
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.
3.
4.
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.
OL-30933-01
Purpose
Enters global configuration mode.
{ |
Creates an access group, and apply a basic IP access list.
query-only
| }
peer
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 switch 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 switch to synchronize
itself to a device whose address passes the access list criteria.
serve-only—Allows only time requests from a device whose address passes the access list criteria.
query-only—Allows only NTP control queries from 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 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 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 switch.
(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.
Software Configuration Guide—Release IOS XE 3.6.0E and IOS 15.2(2)E
Managing the System Time and Date
4-9