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

George N. White III gnwiii at gmail.com
Mon Aug 29 11:49:36 ADT 2011


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>.

> I suspect whatever happened to the DNS/host management
> there was an oddity and it won't happen again in many years.

There are many points of failure for DNS, with potential delays or even
failure to connect to a perfectly good server.

Google claims to offer DNS that is superior in speed/security to what
many users get from their normal DNS:
<http://code.google.com/speed/public-dns/>.
This was based on studies showing DNS server issues were a real problem for
users.

For me, the issue is whether using the IP address reduces my workload
in the long
run.   The IP number is shorter to type when editing sources.list, and
eliminates
several potential failure points against a small risk that the IP
actually changes.
If I change the name to the suggested "workaround" name, at some point I would
want to change back to the public documented name, but it I use the IP
I don't need
to change things until the IP is changed, and in the interm the
reverse DNS search
should lead to the published name.

The main risk with using IP's is that DNS problems that prevent me
from connecting
to the server could also be preventing the site from getting updates.
For  <http://mirror.debian.org/status.html> the recorded errors are:

45:	ERROR: 500 LWP::Protocol::MyFTP: Bad hostname 'mirror.its.dal.ca'
46:	ERROR: 500 Can't connect to mirror.its.dal.ca:80 (Bad hostname
'mirror.its.dal.ca')
47:	ERROR: rsync: getaddrinfo: mirror.its.dal.ca 873: Name or service not known
rsync error: error in socket IO (code 10) at clientserver.c(122)
[Receiver=3.0.7]

-- 
George N. White III <aa056 at chebucto.ns.ca>
Head of St. Margarets Bay, Nova Scotia



More information about the nSLUG mailing list