User manual

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.