几天前，我在网络上设置了 ntp，一切运行正常。一个节点设置为与上游服务器同步，其余节点设置为与上游同步。
昨天我从 CentOS 6.4 更新到 6.5，现在所有 ntp 功能都已停止按预期运行。
为了尝试调试情况，我在上游服务器上运行了以下命令：
$ -> ntpq -pnd
::1: timed out, nothing received
***Request timed out
$ -> ntpq -4 -pnd
1 packets reassembled into response
remote refid st t when poll reach delay offset jitter
==============================================================================
2 packets reassembled into response
*50.116.55.65 64.246.132.14 2 u 42 64 37 77.742 189.392 14.812
2 packets reassembled into response
199.102.46.73 .GPS. 1 u 44 64 37 73.786 216.082 18.406
2 packets reassembled into response
198.60.22.240 .GPS. 1 u 48 64 37 22.617 189.405 15.996
2 packets reassembled into response
127.127.1.0 .LOCL. 10 l 306 64 20 0.000 0.000 0.000
我在节点上得到了相同的结果（除了不同的 IP）。似乎 ntp 服务以某种方式默认为 ipv6，而我尚未配置。我读过一些网站说要将 -4 传递给 ntpd 服务，但我该如何使用 chkconfig 来做到这一点？其他一些阅读表明我应该通过内核禁用 ipv6，但这似乎有点过头了。
有什么建议么？
为了完整性，添加配置文件：
driftfile /var/lib/ntp/drift
# 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
restrict 10.0.0.0 mask 255.255.192.0 nomodify notrap
server 0.centos.pool.ntp.org iburst
server 1.centos.pool.ntp.org
server 2.centos.pool.ntp.org
# In case net access is temporarily down
server 127.127.1.0
fudge 127.127.1.0 stratum 10
答案1
由于它尝试使用 IPv6，您可能希望在配置文件中允许它：
restrict -6 ::1