ec2上的ntpdate：没有适合同步的服务器

我试图打开一个VPC内的一些EC2实例的NTP，从ntpdate开始，因为我的服务器是非常遥远的，我不希望它摆脱。
我遇到了“无服务器适合同步”的错误：

bash-4.1$ sudo ntpdate -u 0.amazon.pool.ntp.org 2 Oct 16:21:05 ntpdate[20767]: no server suitable for synchronization found 

SO上有几个post已经出现这个错误，通常会和防火墙规则绑定在一起。

在这一刻：

• 实例在所有端口上打开，进出（不仅仅是UDP / 123）。
• networkingACL在所有端口上打开和closures
• DNS处于打开状态，0.amazon.pool.ntp.org正在parsing为实际地址。
• NAT似乎正在运行，能够使用wget到达其他外部地址，（也可以通过0.amazon.pool.ntp.orgparsing）

很明显，我不能永远把服务器放在一边，这只是为了诊断问题。 我不知道还有什么可以打开的。

• 一个AWS账户（？），将费用分成多个债务人账户，每个账户都有自己的信用卡
• 如何将一个DNS名称分配给Ansible中的variables？
• AWS VPC通过VPN隧道通信失败
• AWS负载平衡器的安全组不会将stream量转发到后端实例
• Openvpn：客户端可以ping服务器，服务器不能ping客户端

这是诊断跟踪：

 2 Oct 16:25:06 ntpdate[20815]: ntpdate [email protected] Mon Mar 9 14:24:09 UTC 2015 (1) Looking for host 0.amazon.pool.ntp.org and service ntp host found : services.quadranet.com transmit(198.55.111.50) transmit(50.116.55.65) transmit(108.61.194.85) transmit(173.44.32.10) transmit(198.55.111.50) transmit(50.116.55.65) transmit(108.61.194.85) transmit(173.44.32.10) transmit(198.55.111.50) transmit(50.116.55.65) transmit(108.61.194.85) transmit(173.44.32.10) transmit(198.55.111.50) transmit(50.116.55.65) transmit(108.61.194.85) transmit(173.44.32.10) transmit(198.55.111.50) transmit(50.116.55.65) transmit(108.61.194.85) transmit(173.44.32.10) 198.55.111.50: Server dropped: no data 50.116.55.65: Server dropped: no data 108.61.194.85: Server dropped: no data 173.44.32.10: Server dropped: no data server 198.55.111.50, port 123 stratum 0, precision 0, leap 00, trust 000 refid [198.55.111.50], delay 0.00000, dispersion 64.00000 transmitted 4, in filter 4 reference time: 00000000.00000000 Sun, Dec 31 1899 19:00:00.000 originate timestamp: 00000000.00000000 Sun, Dec 31 1899 19:00:00.000 transmit timestamp: d9b966a5.c841bbbb Fri, Oct 2 2015 16:25:09.782 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 server 50.116.55.65, port 123 stratum 0, precision 0, leap 00, trust 000 refid [50.116.55.65], delay 0.00000, dispersion 64.00000 transmitted 4, in filter 4 reference time: 00000000.00000000 Sun, Dec 31 1899 19:00:00.000 originate timestamp: 00000000.00000000 Sun, Dec 31 1899 19:00:00.000 transmit timestamp: d9b966a5.fb750a47 Fri, Oct 2 2015 16:25:09.982 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 server 108.61.194.85, port 123 stratum 0, precision 0, leap 00, trust 000 refid [108.61.194.85], delay 0.00000, dispersion 64.00000 transmitted 4, in filter 4 reference time: 00000000.00000000 Sun, Dec 31 1899 19:00:00.000 originate timestamp: 00000000.00000000 Sun, Dec 31 1899 19:00:00.000 transmit timestamp: d9b966a6.2ea83387 Fri, Oct 2 2015 16:25:10.182 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 server 173.44.32.10, port 123 stratum 0, precision 0, leap 00, trust 000 refid [173.44.32.10], delay 0.00000, dispersion 64.00000 transmitted 4, in filter 4 reference time: 00000000.00000000 Sun, Dec 31 1899 19:00:00.000 originate timestamp: 00000000.00000000 Sun, Dec 31 1899 19:00:00.000 transmit timestamp: d9b966a6.61db63f1 Fri, Oct 2 2015 16:25:10.382 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 2 Oct 16:25:11 ntpdate[20815]: no server suitable for synchronization found 

build议请？