[ntp:questions] NPTdate - difference in packets between -q and not?

Richard B. Gilbert rgilbert88 at comcast.net
Sat Apr 4 13:48:29 UTC 2009


David J Taylor wrote:
> David Woolley wrote:
>> David J Taylor wrote:
>>
>>> What is the difference in the packets sent and received in the two
>>> command formats (I appreciate that -q does not set the clock)?
>>
>> The source port number.  Your friend has a firewall problem.  It is
>> blocking replies to port 123.
> 
> OK, David.  That's certainly consistent with the other problems we've 
> seen.  He claims to be running no software firewall, so perhaps it is 
> something in his router?
> 
> Would the same apply to ntpq -p?  That also works.
> 
> Thanks,
> David

Routers sold into the consumer market generally have configuration 
options to allow or block ports and some can be configured to block 
specific IP addresses or address families.  By default they allow 
responses to outgoing packets and block all other incoming traffic.




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