【Linux】ntp的一些坑。你肯定遇到过

ntpdate提示

19 Jan 10:33:11 ntpdate[29616]: no server suitable for synchronization found

这种问题从下面几个点开始验证

1.查看防火墙是否开通udp的123端口，是udp 无法使用telnet来验证，只能看iptables和硬墙是否有策略

2.如果端口开通，查看服务器端的ntp.conf文件中server是否正常，如果配置有问题，肯定无法使用

3.修改配置是否重新启动ntpd服务

4.查看服务端ntpd进程是否正常

ntpdate -d ntp服务端ip

遇到的几个问题

1.Server dropped:no data

处理办法：网络不通，检查防火墙的udp端口123是否能用，查看服务端的ntpd服务是否启动

[root@ip-192.168.25.10 ~]# ntpdate -d 192.168.25.10
19 Jan 10:24:16 ntpdate[27838]: ntpdate 4.2.6p5@1.2349-o Tue Jun 23 15:38:19 UTC 2020 (1)
Looking for host 192.168.25.10 and service ntp
host found : ip-192.168.25.10.ap-southeast-1.compute.internal
transmit(192.168.25.10)
transmit(192.168.25.10)
transmit(192.168.25.10)
transmit(192.168.25.10)
transmit(192.168.25.10)
192.168.25.10: Server dropped: no data
server 192.168.25.10, port 123
stratum 0, precision 0, leap 00, trust 000
refid [192.168.25.10], delay 0.00000, dispersion 64.00000
ansmitted 4, in filter 4
▽ference time: 00000000.00000000 Mon, Jan 1 1900 8:05:43.000
originate timestamp: 00000000.00000000 Mon, Jan 1 1900 8:05:43.000
transmit timestamp: e3b0c156.2402fb9d Tue, Jan 19 2021 10:24:22.140
filter delay: 0.00000 0.00000 0.00000 0.00000
0.00000 0.00000 0.00000 0.00000
filter offset: 0.000000 0.000000 0.000000 0.000000
0.000000 0.000000 0.000000 0.000000
delay 0.00000, dispersion 64.00000
offset 0.000000

19 Jan 10:24:24 ntpdate[27838]: no server suitable for synchronization found

2.Server dropped: strata too high

这个问题一般都是server端ntp.conf中server行配置了网络ntp的服务端url导致，可以收到ntp的包，但是延迟很高。

 1 [root@ip-192.168.25.10 ~]# ntpdate -d 192.168.25.10
 2 19 Jan 10:33:32 ntpdate[29681]: ntpdate 4.2.6p5@1.2349-o Tue Jun 23 15:38:19 UTC 2020 (1)
 3 Looking for host 192.168.25.10 and service ntp
 4 host found : ip-192.168.25.10.ap-southeast-1.compute.internal
 5 transmit(192.168.25.10)
 6 receive(192.168.25.10)
 7 transmit(192.168.25.10)
 8 receive(192.168.25.10)
 9 transmit(192.168.25.10)
10 receive(192.168.25.10)
11 transmit(192.168.25.10)
12 receive(192.168.25.10)
13 192.168.25.10: Server dropped: strata too high
14 server 192.168.25.10, port 123
15 stratum 16, precision -24, leap 11, trust 000
16 refid [192.168.25.10], delay 0.02573, dispersion 0.00000
17 transmitted 4, in filter 4
18 reference time:    00000000.00000000  Mon, Jan  1 1900  8:05:43.000
19 originate timestamp: e3b0c382.6344a1b6  Tue, Jan 19 2021 10:33:38.387
20 transmit timestamp:  e3b0c382.670289fb  Tue, Jan 19 2021 10:33:38.402
21 filter delay:  0.02574  0.02573  0.02574  0.02573
22          0.00000  0.00000  0.00000  0.00000
23 filter offset: -0.01470 -0.01471 -0.01471 -0.01471
24          0.000000 0.000000 0.000000 0.000000
25 delay 0.02573, dispersion 0.00000
26 offset -0.014712
27
28 19 Jan 10:33:38 ntpdate[29681]: no server suitable for synchronization found

解决办法就是将服务端也开启ntpdate 然后通过ntpdate链接网络url的ntp服务器，然后在ntp.conf中配置server 127.127.1.0   （记住 不是127.0.0.1 这个无效）

在打开ntpq -p 查看是否转为LOCAL了

[root@ip-192.168.25.10 ~]# ntpq -p
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
*LOCAL(0)        .LOCL.           8 l   11   64   17    0.000    0.000   0.000

正确的ntpdate -d 应该是下面的

 1 [root@ip-192.168.25.10 ~]# ntpdate -d 192.168.25.10
 2 19 Jan 10:35:25 ntpdate[30125]: ntpdate 4.2.6p5@1.2349-o Tue Jun 23 15:38:19 UTC 2020 (1)
 3 Looking for host 192.168.25.10 and service ntp
 4 host found : ip-192.168.25.10.ap-southeast-1.compute.internal
 5 transmit(192.168.25.10)
 6 receive(192.168.25.10)
 7 transmit(192.168.25.10)
 8 receive(192.168.25.10)
 9 transmit(192.168.25.10)
10 receive(192.168.25.10)
11 transmit(192.168.25.10)
12 receive(192.168.25.10)
13 server 192.168.25.10, port 123
14 stratum 6, precision -24, leap 00, trust 000
15 refid [192.168.25.10], delay 0.02574, dispersion 0.00000
16 transmitted 4, in filter 4
17 reference time:    e3b0c3eb.878bf296  Tue, Jan 19 2021 10:35:23.529
18 originate timestamp: e3b0c3f3.442fd9c7  Tue, Jan 19 2021 10:35:31.266
19 transmit timestamp:  e3b0c3f3.47e920c0  Tue, Jan 19 2021 10:35:31.280
20 filter delay:  0.02574  0.02574  0.02574  0.02576
21          0.00000  0.00000  0.00000  0.00000
22 filter offset: -0.01465 -0.01465 -0.01465 -0.01466
23          0.000000 0.000000 0.000000 0.000000
24 delay 0.02574, dispersion 0.00000
25 offset -0.014652
26
27 19 Jan 10:35:31 ntpdate[30125]: adjust time server 192.168.25.10 offset -0.014652 sec

ps:以上ip均已做脱敏处理