Comment 9 for bug 787551

More than two month later I still have this problem. The connection to the timeserver seems to be faster:
root@cheetah:/root(34)# ping 10.101.10.20
PING 10.101.10.20 (10.101.10.20) 56(84) bytes of data.
64 bytes from 10.101.10.20: icmp_req=1 ttl=127 time=0.286 ms
64 bytes from 10.101.10.20: icmp_req=2 ttl=127 time=0.315 ms
64 bytes from 10.101.10.20: icmp_req=3 ttl=127 time=0.298 ms
64 bytes from 10.101.10.20: icmp_req=4 ttl=127 time=0.197 ms
64 bytes from 10.101.10.20: icmp_req=5 ttl=127 time=0.354 ms
64 bytes from 10.101.10.20: icmp_req=6 ttl=127 time=0.395 ms
64 bytes from 10.101.10.20: icmp_req=7 ttl=127 time=0.516 ms
64 bytes from 10.101.10.20: icmp_req=8 ttl=127 time=0.388 ms
64 bytes from 10.101.10.20: icmp_req=9 ttl=127 time=0.496 ms
64 bytes from 10.101.10.20: icmp_req=10 ttl=127 time=0.535 ms
64 bytes from 10.101.10.20: icmp_req=11 ttl=127 time=0.221 ms
^C
--- 10.101.10.20 ping statistics ---
11 packets transmitted, 11 received, 0% packet loss, time 9997ms
rtt min/avg/max/mdev = 0.197/0.363/0.535/0.112 ms

But ntpdate still says "Server dropped: no data":

root@cheetah:/root(35)# ntpdate -o 2 -t 5.0 -p 8 -d -d 10.101.10.20
 9 Nov 21:31:30 ntpdate[3227]: ntpdate 4.2.6p2@1.2194-o Wed Jul 28 02:36:37 UTC 2010 (1)
transmit(10.101.10.20)
transmit to 10.101.10.20
receive(10.101.10.20)
transmit(10.101.10.20)
transmit to 10.101.10.20
receive(10.101.10.20)
transmit(10.101.10.20)
transmit to 10.101.10.20
receive(10.101.10.20)
transmit(10.101.10.20)
transmit to 10.101.10.20
receive(10.101.10.20)
transmit(10.101.10.20)
transmit to 10.101.10.20
receive(10.101.10.20)
transmit(10.101.10.20)
transmit to 10.101.10.20
receive(10.101.10.20)
transmit(10.101.10.20)
transmit to 10.101.10.20
receive(10.101.10.20)
transmit(10.101.10.20)
transmit to 10.101.10.20
receive(10.101.10.20)
transmit(10.101.10.20)
10.101.10.20: Server dropped: no data
server 10.101.10.20, port 123
stratum 5, precision -17, leap 00, trust 000
refid [10.101.10.20], delay 0.00000, dispersion 64.00000
transmitted 8, in filter 8
reference time: d084190a.bc06b19f Tue, Nov 9 2010 20:01:30.734
originate timestamp: d084190a.bc06b19f Tue, Nov 9 2010 20:01:30.734
transmit timestamp: d0842e30.a4d34fbb Tue, Nov 9 2010 21:31:44.643
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

 9 Nov 21:31:46 ntpdate[3227]: no server suitable for synchronization found

Nmap identifies the timeserver as:

IP ID Sequence Generation: Busy server or unknown class
Service Info: Host: *.*.*.*; OSs: NetWare, Unix

Any idea besides downgrading of ntp to solve the problem?

There is a similar bug: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=599793