View the server's restrict list, Field descriptions, View the server's restrict list -40 – Alcatel Carrier Internetworking Solutions Omni Switch/Router User Manual

Page 318

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NTP Access Control Menu

Page 12-40

limited

These hosts are subject to a limitation of the number of clients
from the same net. Net in this context refers to the IP notion of
net (class

A

, class

B

, class

C

, etc.). Only the first client limit

hosts that have shown up at the server and that have been
active during the last client limit period (in seconds) are
accepted. Requests from other clients from the same net are
rejected. Only time request packets are taken into account.
Query packets sent by the ntpq and xntpdc programs are not
subject to these limits. A history of clients is kept using the
monitoring capability of xntpd. Thus, monitoring is always
active as long as there is a restriction entry with the limited flag.
For more information on enabling monitoring, see Turn the
Server's Monitoring Facility On or Off
on page 12-31.

ntpport

This is actually a match algorithm modifier, rather than a restric-
tion flag. Its presence causes the restriction entry to be matched
only if the source port in the packet is the standard

NTP

UDP

port (123). Both

ntpport

and

non-ntpport

may be specified. The

ntpport

is considered more specific and is sorted later in the list.

View the Server's Restrict List

The

ntpvres

command allows you to view a list of all the configured restrictions for the

switch. To view a list of configured restriction, enter the

ntpvres

command at the system

prompt. A screen similar to the following appears:

address

mask

count

flags

==============================================================
0.0.0.0

0.0.0.0

12

none

127.0.0.1

255.255.255.255

0

ntpport, ignore

Field Descriptions

The following section describes the fields displayed with the

ntpvres

command.

address

. The

IP

address of the

NTP

entity for which flags have been configured.

mask

. The subnet mask of the

NTP

entity for which flags have been configured.

count

. The number of

NTP

messages from the

NTP

entity that have been affected by the

configured flags.

flags

. The flags configured for this

NTP

entity. For a description of all possible flags, see

Create Restrict Entry/Add Flags to Entry on page 12-39.

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