centos iptables and ntp

Hello all,

I set up ntp and iptables on my centos box (6.4). It looks like iptables is stopping ntp from reaching the server. My /var/log/messages has many entries like this -

Sep  7 11:43:41 solar ntpd[27202]: sendto(194.71.144.71) (fd=22): Operation not permitted
Sep  7 11:44:00 solar ntpd[27202]: sendto(217.115.155.125) (fd=22): Operation not permitted
Sep  7 11:44:44 solar ntpd[27202]: sendto(194.71.144.71) (fd=22): Operation not permitted
Sep  7 11:45:03 solar ntpd[27202]: sendto(217.115.155.125) (fd=22): Operation not permitted
Sep  7 11:45:47 solar ntpd[27202]: sendto(194.71.144.71) (fd=22): Operation not permitted

ntp commands and output -

$ ntpq -p
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
 time.an3k.de    192.53.103.108   2 u   5h  256    0   16.081    3.973   0.000
 pool.ntp.connec 192.36.144.22    2 u   5h  256    0   38.288    2.309   0.000
*ntp0.mediamatic 193.0.0.229      2 u  335 1024  377    9.038    0.684   0.255

$ ntpdate
 7 Sep 19:10:21 ntpdate[6607]: no servers can be used, exiting

$ ntpstat
synchronised to NTP server (130.130.91.183) at stratum 3 
   time correct to within 65 ms
   polling server every 1024 s

I read somewhere that using iptables to open the port without specific source/destination IPs is a risk. So which IPs should I use - ntp.conf has just hostnames.