[Info-vax] What's NTP doing ???

[David Froble]

David Froble wrote:
> JF Mezei wrote:
>> On 14-02-01 14:10, David Froble wrote:
>>
>>> However, on both a VAX and an Alpha, I'm seeing about 1 I/O per 
>>> second on the NTP_1 process.  Anybody know what NTP is doing to 
>>> generate I/Os so often? 
>>
>>
>> They are bored, so it is the equivalent of twiddling their thumbs :-)
>>
>> Many ntp servers have parameters to set polling intervals. Can't
>> remember if VMS has that.
>>
>> CISCO routers do not have such parameters, but they adjust the interval
>> based on variations in latency/line conditions.  Minimum is 64 seconds
>> if I recall properly.
>>
>>
>> BTW, unless you want to be a public NTS server, there is no reason to
>> keep inboud 123 open.  Your servers make outboud requests to
>> authoritative servers but don't need to accept requests from outside
>> your lan.
>>
>> This prevents your server from being told to generate the "monlist". But
>> does not prevent your IP address from receiviung the result of a monlist
>> issued to some foreign server with your forged IP address.
>>
>> Your system may dismiss those packets because they are addressed to a
>> post that is not being listened to, but it still gnerates traffic.
>>
> 
> That's not it.  There is no way from outside to get into my network. I'm 
> not saying that I've set up good protection, I'm saying that Verizon has 
> things set up, probably to save on having assigned IP addresses, that 
> the IP address they assign to me is not accessable from the outside.  
> This actually is not good, for me.
> 
> It's as if NTP is doing constant (1 per second) polling of something ...

Ok, got interested, did some looking ...

  2 Feb 04:43:39 ntp[566]: offset: 0.001564 sec  freq: 13.533 ppm  poll: 
1024 sec
   error: 0.003185
  2 Feb 05:43:42 ntp[566]: offset: -0.000629 sec  freq: 13.337 ppm 
poll: 1024 se
c  error: 0.003476

  2 Feb 06:43:45 ntp[566]: offset: -0.010766 sec  freq: 12.807 ppm 
poll: 1024 se
c  error: 0.003022
  2 Feb 07:43:49 ntp[566]: offset: -0.009745 sec  freq: 12.748 ppm 
poll: 1024 se
c  error: 0.003044
  2 Feb 08:43:52 ntp[566]: offset: -0.002093 sec  freq: 13.131 ppm 
poll: 1024 se
c  error: 0.002265

Apparently it's talking to the clock every 2-4 seconds ....