[nSLUG] New Nova Scotia Open Source mirror, mirror.its.dal.ca

D G Teed donald.teed at gmail.com
Mon Aug 29 12:29:52 ADT 2011


On Mon, Aug 29, 2011 at 11:49 AM, George N. White III <gnwiii at gmail.com> wrote:
> On Sun, Aug 28, 2011 at 7:56 PM, D G Teed <donald.teed at gmail.com> wrote:
>
>> On Sun, Aug 28, 2011 at 6:05 PM, George N. White III <gnwiii at gmail.com>
>> wrote:
>>>
>>> or you can use the IP address: 192.75.96.254
>>>
>>> It makes sense to use IP addresses for important servers because
>>> DNS problems tend to occur more often than IP address changes
>>>
>>
>> I dunno about that concept.  I can't speak for Dal, but we often
>> upgrade services with the idea people are accessing it by hostname.
>> It would be rare to transfer the IP to a new server when migrations are
>> done.
>> We typically encourage access to an alias name and that floats around
>> as needed.
>
> Changing the IP for a server can cause problems for clients with caching
> resolvers such as SGI IRIX64  and Windows XP and later
> <http://support.microsoft.com/kb/318803>.

Typically I combat DNS caching by keeping the legacy service
running on the older server with the original IP until access logs
show we don't have many people relying on the legacy system.

The key is to not restart the service on the legacy system after
the hostname has been given to a new system.  Say for apache,
it will continue answering to the hostname it had when the
service was launched if that is what the client also believes
is the IP for this host.

As for the original subject, mirror.its.dal.ca is accessible again.



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