I'm having some problems with synchronization with an NTP server.

1) The NTP daemon doesn't sync the system clock at all, even though it's running (confirmed with /etc/init.d/ntp status). Forcing to sync with ntpd -q or ntpd -gq does not work either.

2) Stopping the NTP daemon and syncing manually with ntpdate does give me the following output:

~# ntpdate -d 0.debian.pool.ntp.org
6 Nov 16:48:53 ntpdate[4417]: ntpdate [email protected] Sat May 12 09:07:19 UTC 2012 (1)
transmit(79.132.237.5)
receive(79.132.237.5)
transmit(85.234.197.2)
receive(85.234.197.2)
transmit(194.50.97.34)
receive(194.50.97.34)
transmit(79.132.237.1)
receive(79.132.237.1)
transmit(79.132.237.5)
receive(79.132.237.5)
transmit(85.234.197.2)
receive(85.234.197.2)
transmit(194.50.97.34)
receive(194.50.97.34)
transmit(79.132.237.1)
receive(79.132.237.1)
transmit(79.132.237.5)
receive(79.132.237.5)
transmit(85.234.197.2)
receive(85.234.197.2)
transmit(194.50.97.34)
receive(194.50.97.34)
transmit(79.132.237.1)
receive(79.132.237.1)
transmit(79.132.237.5)
receive(79.132.237.5)
transmit(85.234.197.2)
receive(85.234.197.2)
transmit(194.50.97.34)
receive(194.50.97.34)
transmit(79.132.237.1)
receive(79.132.237.1)
server 79.132.237.5, port 123
stratum 2, precision -20, leap 00, trust 000
refid [79.132.237.5], delay 0.05141, dispersion 0.00145
transmitted 4, in filter 4
reference time:    d624e3b1.f490b90d  Wed, Nov  6 2013 16:50:09.955
originate timestamp: d624e457.eaaf787c  Wed, Nov  6 2013 16:52:55.916
transmit timestamp:  d624e36c.4a7036fd  Wed, Nov  6 2013 16:49:00.290
filter delay:  0.08537  0.05141  0.05151  0.06346
         0.00000  0.00000  0.00000  0.00000
filter offset: 235.6038 235.6087 235.6095 235.6068
         0.000000 0.000000 0.000000 0.000000
delay 0.05141, dispersion 0.00145
offset 235.608782

server 85.234.197.2, port 123
stratum 2, precision -20, leap 00, trust 000
refid [85.234.197.2], delay 0.05151, dispersion 0.00336
transmitted 4, in filter 4
reference time:    d624e3e7.dc6cd02b  Wed, Nov  6 2013 16:51:03.861
originate timestamp: d624e458.1c91031f  Wed, Nov  6 2013 16:52:56.111
transmit timestamp:  d624e36c.7da1d882  Wed, Nov  6 2013 16:49:00.490
filter delay:  0.05765  0.07750  0.06013  0.05151
         0.00000  0.00000  0.00000  0.00000
filter offset: 235.6048 235.6014 235.6035 235.6078
         0.000000 0.000000 0.000000 0.000000
delay 0.05151, dispersion 0.00336
offset 235.607826

server 194.50.97.34, port 123
stratum 3, precision -23, leap 00, trust 000
refid [194.50.97.34], delay 0.03021, dispersion 0.00090
transmitted 4, in filter 4
reference time:    d624e38d.2bce952c  Wed, Nov  6 2013 16:49:33.171
originate timestamp: d624e458.4dbbc114  Wed, Nov  6 2013 16:52:56.303
transmit timestamp:  d624e36c.b0d38834  Wed, Nov  6 2013 16:49:00.690
filter delay:  0.03030  0.03636  0.03091  0.03021
         0.00000  0.00000  0.00000  0.00000
filter offset: 235.6095 235.6085 235.6098 235.6105
         0.000000 0.000000 0.000000 0.000000
delay 0.03021, dispersion 0.00090
offset 235.610589

server 79.132.237.1, port 123
stratum 3, precision -20, leap 00, trust 000
refid [79.132.237.1], delay 0.05113, dispersion 0.00305
transmitted 4, in filter 4
reference time:    d624dfcb.6acea332  Wed, Nov  6 2013 16:33:31.417
originate timestamp: d624e458.838672ad  Wed, Nov  6 2013 16:52:56.513
transmit timestamp:  d624e36c.e405181c  Wed, Nov  6 2013 16:49:00.890
filter delay:  0.06345  0.05113  0.05681  0.05656
         0.00000  0.00000  0.00000  0.00000
filter offset: 235.6087 235.6038 235.6010 235.6074
         0.000000 0.000000 0.000000 0.000000
delay 0.05113, dispersion 0.00305
offset 235.603888

 6 Nov 16:49:00 ntpdate[4417]: step time server 79.132.237.5 offset 235.608782 sec

Clearly, ntpdate can reach the NTP server(s), but after checking the clock, it hasn't changed and is still displaying the wrong time.

Any ideas what would be the problem would be much appreciated.