ntpdate ip 失败，但-d测试能成功，这是为什么

pusshi

[root@CentOS ~]# ntpdate 202.112.29.82
5 Dec 00:32:58 ntpdate[9615]: no server suitable for synchronization found     #失败

[root@CentOS ~]# ntpdate -d 202.112.29.82  #这个能成功，为什么
5 Dec 00:33:23 ntpdate[9616]: ntpdate 4.2.2p1@1.1570-o Thu Jan 22 02:51:26 UTC 2009 (1)
Looking for host 202.112.29.82 and service ntp
host found : dns1.synet.edu.cn
transmit(202.112.29.82)
receive(202.112.29.82)
transmit(202.112.29.82)
receive(202.112.29.82)
transmit(202.112.29.82)
receive(202.112.29.82)
transmit(202.112.29.82)
transmit(202.112.29.82)
server 202.112.29.82, port 123
stratum 2, precision -20, leap 00, trust 000
refid [202.112.29.82], delay 0.06815, dispersion 8.00017
transmitted 4, in filter 4
reference time:    da0c3ebd.b601fe53  Sat, Dec  5 2015  0:33:01.710
originate timestamp: da0c3ed6.a883cb68  Sat, Dec  5 2015  0:33:26.658
transmit timestamp:  da0c3ed3.7d1f926c  Sat, Dec  5 2015  0:33:23.488
filter delay:  0.07079  0.06815  0.06844  0.00000
         0.00000  0.00000  0.00000  0.00000
filter offset: 3.191263 3.190816 3.190946 0.000000
         0.000000 0.000000 0.000000 0.000000
delay 0.06815, dispersion 8.00017
offset 3.190816

5 Dec 00:33:24 ntpdate[9616]: step time server 202.112.29.82 offset 3.190816 sec

lyhabc

-d      Enable the debugging mode, in which ntpdate will go through
               all  the steps, but not adjust the local clock. Information
               useful for general debugging will also be printed.
调试模式已而