故障现象：
ntpdate: no server suitable for synchronization found
解决办法:
~]# ntpdate -b -u pool.ntp.org
ntpdate命令帮助：
~]# man ntpdate
COMMAND LINE OPTIONS
-b Force the time to be stepped using the settimeofday() system call, rather than slewed (default) using the
adjtime() system call. This option should be used when called from a startup file at boot time.
-u Direct ntpdate to use an unprivileged port for outgoing packets. This is most useful when behind a fire-
wall that blocks incoming traffic to privileged ports, and you want to synchronize with hosts beyond the
firewall. Note that the -d option always uses unprivileged ports.
ntpdate同步时间时错误: no server suitable for synchronization found
原文：http://zliang90.blog.51cto.com/3001993/1556984