b. 设置权限，我的所有restrict条目如下

restrict -4 default kod notrap nomodify nopeer noquery
restrict -6 default kod notrap nomodify nopeer noquery
# Local users may interrogate the ntp server more closely.
restrict 127.0.0.1
restrict ::1
# Clients from this (example!) subnet have unlimited access, but only if
# cryptographically authenticated.
#restrict 192.168.123.0 mask 255.255.255.0 notrust
restrict 192.168.0.0 mask 255.255.255.0

 3. 重启ntp服务器

　　/etc/init.d/ntp restart

 4. 查看服务器是否工作正常

　　在服务器运行

　　Java代码

ntpq -p

　　二、工作站同步

　　好了，测试一下吧，假设你的新服务器IP地址为192.168.0.7。在客户端运行如下命令：

　　ntpdate -u 192.168.0.7

　　同步成功后，将会显示如下：

　　6 Mar 15:44:24 ntpdate[9921]: adjust time server 192.168.0.7 offset -0.007277 sec

　　三、交换机同步

　　Cisco IOS

　　Java代码

ciscorouter> enable
password: *********
ciscorouter# config t
ciscorouter(config)# ntp update-calendar
ciscorouter(config)# ntp server 192.168.0.4
ciscorouter(config)# ntp server 192.168.0.7
ciscorouter(config)# exit
ciscorouter# wr mem

　　Dell 6248

　　Java代码

dell6248-corner>en
dell6248-corner#configure
dell6248-corner(config)#sntp server 192.168.0.7
dell6248-corner(config)#

　　四、一些常见的时间服务器

　　210.72.145.44　 ── (国家授时中心服务器IP地址)

　　133.100.11.8　 ── 日本 福冈大学

　　time-a.nist.gov 129.6.15.28 ── NIST, Gaithersburg, Maryland

　　time-b.nist.gov 129.6.15.29 ── NIST, Gaithersburg, Maryland

　　time-a.timefreq.bldrdoc.gov 132.163.4.101 ── NIST, Boulder, Colorado

　　time-b.timefreq.bldrdoc.gov 132.163.4.102 ── NIST, Boulder, Colorado

　　time-c.timefreq.bldrdoc.gov 132.163.4.103 ── NIST, Boulder, Colorado

　　utcnist.colorado.edu 128.138.140.44 ── University of Colorado, Boulder

　　time.nist.gov 192.43.244.18 ── NCAR, Boulder, Colorado

　　time-nw.nist.gov 131.107.1.10 ── Microsoft, Redmond, Washington

　　nist1.symmetricom.com 69.25.96.13 ── Symmetricom, San Jose, California

　　nist1-dc.glassey.com 216.200.93.8 ── Abovenet, Virginia

　　nist1-ny.glassey.com 208.184.49.9 ── Abovenet, New York City

　　nist1-sj.glassey.com 207.126.98.204 ── Abovenet, San Jose, California

　　nist1.aol-ca.truetime.com 207.200.81.113 ── TrueTime, AOL facility, Sunnyvale, California

　　nist1.aol-va.truetime.com 64.236.96.53 ── TrueTime, AOL facility, Virginia

　　五、使用Python脚本来获取时间

#!/usr/bin/python
from socket import *
import struct,os,time,sys
# Script to set Linux hardware clock (/usr/sbin/hwclock) from an NTP
# time server.   Run as "setclock.py" to simply print the time from
# the NTP server.  Run as "setclock.py --set" to set the Linux
# hardware clock (as the super user, of course).
# Based on Simon Foster's simple SNTP client from ASPN Python cookbook.
# Adapted by Paul Rubin; this script lives at:
#    http://www.nightsong.com/phr/python/setclock.py
time_server = ('time.apple.com', 123)
# time.apple.com is a stratum 2 time server.  (123 is the SNTP port number).
# More servers info can be found at
#
#   http://www.eecis.udel.edu/~mills/ntp/servers.htm
#
# Note it's considered antisocial to use a stratum 1 server (like NIST)
# for purposes like this which don't need extreme accuracy (i.e. syncing
# your own big NTP network).  See www.ntp.org for more info.
#
# You could also use time.windows.com (Microsoft server) which syncs
# all Windows XP machines everywhere, so it can presumably handle lots
# of clients.
# number of seconds between NTP epoch (1900) and Unix epoch (1970).
TIME1970 = 2208988800L      # Thanks to F.Lundh
client = socket( AF_INET, SOCK_DGRAM )
data = 'x1b' + 47 * ''
client.sendto(data, time_server)
data, address = client.recvfrom( 1024 )
if data:
print 'Response received from', address,'n'
t = struct.unpack( '!12I', data )[10]
if t == 0:
raise 'invalid response'
ct = time.ctime(t - TIME1970)
print 'Current time = %sn' % ct
if len(sys.argv) > 1 and sys.argv[1] == "--set":
os.system("/usr/sbin/hwclock --set '--date=%s'"% ct)
else:
raise 'no data returned'

　　上面这个脚本原址在这里，http://www.nightsong.com/phr/python/setclock.py， http://www.bt285.cn， http://www.guihua.org。使用方式如下：

　　$ python setclock.py

　　Response received from ('17.151.16.23', 123)

　　Current time = Fri Mar　 6 16:03:19 2009