[ntp:questions] NTP stops when client address changes?

David J Taylor david-taylor at blueyonder.not-this-part.nor-this.co.uk.invalid
Thu Aug 6 11:57:40 UTC 2009


Maarten Wiltink wrote:
> "David J Taylor"
> <david-taylor at blueyonder.not-this-part.nor-this.co.uk.invalid> wrote
> in message news:Qlxem.64507$OO7.50218 at text.news.virginmedia.com...
>
> [...]
>> However, why would the communication fail when the client address
>> changed? I thought that the sending address was part of any UDP
>> packet, so that if the client address changed, things should carry
>> on working. Would NTP normally stop working like this, or is there
>> something in
>> the user's network configuration which isn't quite right?  This
>> isn't an IT guru, just a regular Windows user connecting to his
>> regular ISP via an ADSL modem.....
>
> It may be the local socket that stops working when the network
> interface changes underneath it. Is this a one-machine actual modem,
> as opposed to the more usual router? I'd expect the latter to involve
> NAT and thus shield its clients from the specific bit that changes.
> But a dedicated modem connection might have this exact effect.
>
> Groetjes,
> Maarten Wiltink

Thanks, Maarten.  As far as I know, this is a standard PC talking to a "BT 
Home Hub" router.  There is some evidence that /something/ happened to the 
router, as the user commented:

  "Have just tried to access my BT Home Hub to check it's status, only to 
find the fields for "username", "password" and "save details" had all gone 
blank. Have had to re-input to gain access to the hub settings."

I suspect what he means by "gone blank" is that the Web browser had not 
retained the settings as he expected it to, although I don't know this 
particular router.  In fact, it seems to be a router and quite a lot more. 
I also don't know whether the client PC's IP address changed or not.

Anyway, it seems that your understanding is the same as mine, that even if 
a router's wide-area IP address changes, NTP on a PC should keep working.

Cheers,
David 




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