Re: [opensuse] RE: Have you experienced a general sligish DNS resolution - OT - Just slightly
- From: Registration Account <alpha096@xxxxxxxxxx>
- Date: Mon, 21 May 2007 12:06:33 +1000
Thanks for your comment. I understand I can trust a cached DNS server to
just do what is can do without defining zones, however in this case I
don't want to let it do what it wants to - if I did it would probably
just ask my ISP DNS servers first and then other local DNS servers.
Why I elected to define external zones is that I wanted a cached answer
from a source well outside the country - so in some ways I have
circumvented a situation where a cached answer could come from a local
source.
It is so difficult to put into words the difficulty a large very
isolated country faces in both its own local telecommunications
structure and then limitation of exiting the country without making
possibly 20 hops.
By guiding the cached DNS server I have set up, I have just circumvented
the number of local hops and I love your expression ( I don't know but I
know someone who might) its priceless. In this case the someone who
might know may be 20 or more hops away.
Again, this situation really does not effect anyone else in the world
because of proximity and small amounts of hops. Being so isolated with a
population very dependant on I.T and so hugely isolated from anything
places great strain on our public comms infrastructure which internally
is quite good, however at some stage everything needs to exit the
country, and that's where the bottleneck starts.
Until the recent release of the last satellite, there was even
limitations on telephone ISD. At peek times, if I needed to call O/S, I
would sometimes get a "all overseas lines are busy - please try later".
5 years ago if you wanted to call overseas on Christmas day, you had to
book your calls days in advance. Despite ISD being available at that
time, the only way to guarantee a telephone call O/S was to book it days
in advance - sounds frightening but that's the cost of isolation.
The new satellite went up about 4 years ago - Things are easy now.
However large comms dependant companies I.E Qantas (Airline) has its own
private satellite - just for itself.
There is of course, unlimited capacity for military/government use. AU
has a huge U.S base in the middle of the desert which forms an enormous
parts of US early warning systems, and AU radio telescope transmitted
man landing on the moon to the whole world.
Enough rubbish from me.
#
I will remove the external zones and have a look at its performance just
the same.
Scott =-O
G T Smith wrote:
Registration Account wrote:
I would be interested in others feeling/experience about the very slow
resolution of browser enquiries of typical ISP - Particularly if you are
in Australia.
I ran some stats on my ISP's DNS servers ability to resolve enquiries -
The stats were surprising in the number of re-try and Drops. My ISP is a
real one and not a partition of bigpond or optusnet. This is
particularly noticeable now my speed has increased to min 24000/1000kbps
via a DSLAM link.
For others it is interesting that Australia being so isolated; the
amount of bandwidth available to get out of the country to the nearest
major hub is limited and ultimate accessibility to TLD's requires an
enormous amount of hops. A situation you don't every need to think about
in North America or Europe.
To illustrate our delima all you need to do is a traceroute on you ISP's
DNS server(s) in .AU.
To try to overcome the situation I have set-up my own DNS server - to
make all my enquiries and rightly or wrongly I have added zones well up
the TLD ladder - I'll probably get kicked off some of my zones but s far
o.k (My first zone is a root server in Japan)
Put simply the enquiry is
Has anyone (particularly living in AU) noticed a slow response or
incomplete resolution of DNS from their ISP.
My apologies first and foremost for what appears to be a parochial
issue. I hate being that way.
Scott
You do not normally need to explicitly define any external zones to
setup a cache-only DNS, all you need to define is your internal zones
and any external zones that you own and manage. A cache-only DNS should
speed up address resolution after an address has been initially
resolved. (As I understand it you would need to come to an arrangement
with the controller of the zones host server owners to host a copy of a
zone that people external to your environment can query).
DNS servers usually are organised hierarchically, and the way the query
is actually processed varies. A DNS server can be configured to resolve
the request itself if it does not know about a particular address, in
which case the requester will get an authoritative response and you will
see little of the resolution process, or it can be configured to
effectively to give a "I dont know but I know someone who might"
response, and the DNS server will respond with information on which
server to query for the address. Depending where you are in the domain
hierarchy in relation to your target this can involve a number of
redirections. This is normal.
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