Rhel5 配置NTP服務

1.       安裝軟體包：

Yum install ntp

Ntp的配置檔案是/etc/ntp.conf，工作目錄是/etc/ntp/,接着編輯/etc/ntp.conf檔案。

2.       服務端配置：

IP:192.168.1.110

編輯/etc/ntp.conf檔案：

[root@rhel5 ~]# cat /etc/ntp.conf

# Permit time synchronization with our time source, but do not

# permit the source to query or modify the service on this system.

restrict default kod nomodify notrap nopeer noquery

restrict -6 default kod nomodify notrap nopeer noquery

# Permit all access over the loopback interface.  This could

# be tightened as well, but to do so would effect some of

# the administrative functions.

restrict 127.0.0.1

# Hosts on local network are less restricted.

restrict 192.168.1.0 mask 255.255.255.0 nomodify notrap(允許内網通訊)

restrict 0.0.0.0 mask 0.0.0.0 nomodify notrap noquery notrust(禁止其他ip來更新時間)

# Use public servers from the pool.ntp.org project.

server 0.pool.ntp.org(redhat預設情況下是server 0.redhat.pool.ntp.org)

server 1.pool.ntp.org(redhat預設情況下是server 1.redhat.pool.ntp.org)

server 2.pool.ntp.org(redhat預設情況下是server 2.redhat.pool.ntp.org)

#broadcast 192.168.1.255 key 42         # broadcast server

#broadcastclient                        # broadcast client

#broadcast 224.0.1.1 key 42             # multicast server

#multicastclient 224.0.1.1              # multicast client

#manycastserver 239.255.254.254         # manycast server

#manycastclient 239.255.254.254 key 42  # manycast client

# Undisciplined Local Clock. This is a fake driver intended for backup

# and when no outside source of synchronized time is available.

server 127.127.1.0

fudge   127.127.1.0 stratum 10

# Drift file.  Put this in a directory which the daemon can write to.

# No symbolic links allowed, either, since the daemon updates the file

# by creating a temporary in the same directory and then rename()'ing

# it to the file.

driftfile /var/lib/ntp/drift (driftfile 選項，則指定了用來儲存系統時鐘頻率偏差的檔案， ntpd程式使用它來自動地補償時鐘的自然漂移， 進而使時鐘即使在切斷了外來時源的情況下，仍能保持相當的準确度)

# Key file containing the keys and key identifiers used when operating

# with symmetric key cryptography.

keys /etc/ntp/keys

# Specify the key identifiers which are trusted.

#trustedkey 4 8 42

# Specify the key identifier to use with the ntpdc utility.

#requestkey 8

Logfile /var/log/ntp.log(定義日志資訊)

# Specify the key identifier to use with the ntpq utility.

#controlkey 8

restrict 0. pool.ntp.org mask 255.255.255.255 nomodify notrap noquery

restrict 1. pool.ntp.org mask 255.255.255.255 nomodify notrap noquery

如果restric 後面不帶參數，表示可以允許全部權限.以上三個影響/etc/ntp/ step-tickers這個檔案，它會随着/etc/ntp.conf檔案的變化而變化。

/etc/sysconfig/clock是用來設定時區的檔案，例如：

[root@rhel5 ntp]# cat /etc/sysconfig/clock

# The ZONE parameter is only evaluated by system-config-date.

# The timezone of the system is defined by the contents of /etc/localtime.

ZONE="Asia/Chongqing"

UTC=true

ARC=false

/usr/share/zoneinfo這個目錄裡規定了各主要時區的時間設定檔案，例如重慶：/usr/share/zoneinfo/Asia/Chongqing

如果想把同步好的時間寫入BIOS裡，就要設定/etc/sysconfig/ntp檔案，将其中的SYNC_HWCLOCK=no更改為SYNC_HWCLOCK=yes。

啟動ntp服務：

[root@rhel5 ntp]# service ntpd restart

Shutting down ntpd: [  OK  ]

ntpd: Synchronizing with time server: [  OK  ]

Starting ntpd: [  OK  ]

[root@rhel5 ntp]#chkconfig ntpd on

3.       用戶端的設定：

可以通過使用system-config-time來設定，将其中的時間伺服器更改為192.168.1.110即可，或者使用ntpdate  -u 192.168.1.110來和時間伺服器同步。切記更改完以後要重新啟動NTP服務，使其生效。或者使用crontab  -e來編輯：

*/5 * * * * /usr/sbin/ntpdate  -u 192.168.1.110 表示每五分鐘同步一次。重新開機crond服務即可。

可以使用ntpq –p檢視同步狀态