[Gllug] Routing strangeness

[Chris Bell]

On Sat 23 Oct, Adrian McMenamin wrote:
> 
> On Saturday 23 Oct 2004 15:41, Chris Bell wrote:
> 
> >
> >    It could be down to DNS refresh times somewhere, either within your
> > internal system or your outside contacts.
> 
> Could you explain this a bit more? Thanks.

   The DNS system does a look-up on an address name to find the numerical IP
address. This is stored in an authoritive file on a nameserver, together
with the serial number for that file, time-to-live, plus the refresh, retry,
and expire times for data on that file. There is enough character space
available to have the full date and 00 to 99 as the serial number in the
form YYYYMMDDnn.
   Any DNS query which collects data from the file should attempt to refresh
the data after the refresh time, but if that fails retry after the retry
time, and if all fails expire the data at the expiry time. Depending on the
system, it may only check that the serial number is unchanged and not do a
full refresh on every check.

-- 
Chris Bell

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