NTP does not work on 3750G

[CHM1]

I configured
"ntp server 129.132.2.21 key 0 prefer"
on a catalyst 3750G-12S but the clock on the catalyst is not updated.
A similar command on a small 831 router :
"sntp server 129.132.2.21"
works fine.

A sniffer shows that the dialog between the switch and 129.132.2.21 (Swiss Internet time server) seems OK.

What's happening ?

 

[CHM1]

When i include a "deb ntp packets" and "deb ntp validity" command i get the message :
NTP: packet from 190.9.0.1 failed validity tests 20
Peer/Server Clock unsynchronized

Where to find information on this error message ?

Also the polling interval between ntp resquests seems to be 64 seconds. How to change this polling ?

Thanks .

 

[InDenial]

I searched cisco.com and found that there is no key 0 and that you have to enable ntp authentication....

check :

http://www.cisco.com/en/US/products..._guide_chapter09186a008021267e.html#wp1043077

InDenial