[CentOS] ntptrace ***Request timed out with stock C6 ntpd

Following the recent ntp posts I decided to check my setup with ntptrace.

localhost: stratum 3, offset -0.000020, synch distance 0.016330
81.95.117.62: timed out, nothing received
***Request timed out

service ntpd status
ntpd (pid  3018) is gestart...

grep server /etc/ntp.conf | grep -v "#"
server 0.centos.pool.ntp.org iburst
server 1.centos.pool.ntp.org iburst
server 2.centos.pool.ntp.org iburst
server 3.centos.pool.ntp.org iburst

ntpq> peer
      remote           refid      st t when poll reach   delay offset  jitter
==============================================================================
+85.234.199.227  193.190.230.65   2 u  135 1024  377   29.759 -0.218  48.373
*79.132.231.103  193.190.230.66   2 u  328 1024  377   41.639 1.487  12.891
+195.200.224.66  193.67.79.202    2 u  958 1024  377   13.179 1.036  87.857
+81.95.117.62    193.67.79.202    2 u  343 1024  377   23.321 -1.759  24.933

I've tested on 3 C6 hosts and everyone gives a ***Request timed out. (everytime with an other host)

Is there something wrong with my setup or with my testing?

Thanks
Patrick