Subject: WebAddress resolutions

From: USELESS SSELESU <[email-masked]>
Date: Fri, 21 Sep 2001 04:29:15 -0700 (PDT)

Regards to all IETF members,

               It is said that more steps a man
ascends the more he has to remember how many steps he
ascended.

               Same is the case with me. I plan to
join as a fledgling software developer someday without
knowing the intricacies of the trade!

               I posted the question below in the
Yahoo webrings and somebody had this mailing-list link
where I was told a better response might be tendered.

               Am wondering how and where the
webaddress mappings taking place? Meaning if I type
www.xyz.com in a browser and (say) this xyz.com is
running on 212.34.54.89, then does my Internet Service
Provider lookup every place right from 0.0.0.0 to
255.255.255.255? And finally is that how my ISP gets a
match and says voila I got it and fetches the HTML
page on xyz.com?

              Looking it from the hosting fella's side
(lets assume this host is the owner of 212.34.54.89),
supposing he has undertaken a contract to host
somebody's site. As soon as he starts the hosting does
he need to notify someone that hey please store this
into your database tables that this particular place
212.34.54.89 has www.xyz.com running on it? Is there a
centralized server out there which performs the
mammoth task of storing all the sites and the
addresses on which they are running?

             There must be some such centralized
server, to which all ISPs connect to and refer, or
else my ISP has to start from 0.0.0.0 till
255.255.255.255, and secondly there might be the
possibility that xyz.com is running on two different
places say on 212.34.54.89 and 65.34.219.102 also, in
which case ISPs are going to raise their hands in
helplessness and cry to heaven I cant find the real
one!

            Point is who owns this centralized server?
Also all these hosting fellas like Verio.com from whom
do they purchase these things 212.34.54.89?
NetWorkSolutions?

            Sorry for wasting your time. And extremely
sorry for the bad English and the bad grammar.
                                              
weblogic

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---

From: Jon Crowcroft <[email-masked]>
Date: Fri, 21 Sep 2001 13:32:31 +0100

In message <[email-masked]>, USELESS SSELES

 >>match and says voila I got it and fetches the HTML

that depends what OS they are running - if its
portholes 7.3, then yes, but if its leanix 11.0, esp. the one
running microlite underware release 2 or grater, then there's a hash
function from every www to every ip addr which was reported in
acm sitcomm 77 (not online) although there's a claim that it was in
fact discivered in station exx by albert turning and colleagues in
1943, but under the british 50 year rule, has not been published yet
(the british secret service count years differently to, but i can't
tell you their algorithm as that is secret to).

one reason why www sites are so low to look up is that the portholes
operating system actually also looks up 
aaa.xyz.com
bbb.xyuz.com
...
in case you might want to look at those too soon

in fact, its pretty clever - if you have the internationalized version
it also looks them up in 143 different alphabets, and also caches the
kanji and other iconic maps for you client side

the key advantage of  portholes is that once you have accessed one web
site, yopu need never look at any others, and you certainyl dont need
any of those pesky hard to use search engines.

the main down side is that you also need a peta-store - there's some
you're not allowed into countries that are cyberabies virus
free with a peta-bite - there's good evndicen that most people with a
petabite have the virus somewhere on disk and its only a matter of
time before everyone else gets it

the other neat thing is that after one access, you can hang up your
ISP account for ever

the neat thing about the leanix hash function is that it operates the
other way around, so that you dont need more than 1 pixel display, 1
byte of memory and 1 cps processor - in fact you dont need any users
either, which can be a bonus if you are a sysadmin [ref LISA 1999
paper on "users are the enemy"]

hash functions are very useful for many things - for example you can
invite your friends around to an before work hash function - it makes a
nice change to an after work barbeque

   jon

---

From: "Thor Harald Johansen" <[email-masked]>
Date: Fri, 21 Sep 2001 17:29:23 +0200

> tell you their algorithm as that is secret to).

If I'm not completely mistaken, this is good old fashion bull. It's a joke.

Domain names (www.something.xyz) are resolved using a network of DNS (Domain
Name Service) servers. There are in fact a few central servers to this
system, but they usually don't serve the crowds. This is the job of each
ISPs own DNS servers, wich are updated frequently with new entries from the
central DNSes.

These servers also contains information for reverse resolving. That is to
find out wich IPs have been pointed to by a domain. The Internet would work
fine without domain names. It would just be a bit harder to use (you'd have
to type http://64.12.50.249/ instead of http://www.cnn.com/). I belive DNS
came a long time after IP addresses. :)
--
Thor

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---

From: Jon Crowcroft <[email-masked]>
Date: Fri, 21 Sep 2001 16:40:29 +0100

>>If I'm not completely mistaken, this is good old fashion bull. It's a joke.
 
correct - i guess i should have put a
:-)
for the clueless

note that given most names are of the form
foo.com
and are issued by a small number of authorities rather than the
original design goal of DNS being very very
distributed (and replicated) and hierarchical, actually 
a fixed allocation of client/root server, and a hash lookup
implementation in the root/gTLD servers would actually work for about
95% of systems and maybe a lot better than currently:

given typical findings on the effectiveness of the access protocols
and of cacheing, e.g. see
"DNS Performance and the Effectiveness of Caching," 
by Jaeyeon Jung, Emil Sit, Hari Balakrishnan, and Robert Morris, is at
http://nms.lcs.mit.edu/papers/dns-imw2001.html

it might be wise to move to a more centralised system and be
honest:-)

 >>came a long time after IP addresses. :)
 
and took nearly as long to depoy as ipv6 and ip multicast:-)

i recall doing a comparison of druid and bind at UCL in the mid-late
1980s....about 7 years after we switched from ncp to tcp/ip...

 cheers

   jon

---

From: Joel Jaeggli <[email-masked]>
Date: Fri, 21 Sep 2001 09:18:34 -0700 (PDT)

try typing "how does dns work" google... It will get you a couple of
reasonable summaries...

try this one for a start:

http://hotwired.lycos.com/webmonkey/webmonkey/geektalk/97/03/index4a.html

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---

From: Lloyd Wood <[email-masked]>
Date: Fri, 21 Sep 2001 19:26:49 +0100 (BST)

> If I'm not completely mistaken, this is good old fashion bull. It's a joke.

Yup. Give an education only to those who pay for it, eh?

It strikes me that since the student is increasingly identified by
universities as a consumer - a paying customer - the relative value of
the university's service of delivering education as a product would be
increased by denigrating/polluting the commons as much as possible;
spreading free misinformation could be a valid strategy used to
increase the relative value of a university's services.

This might be why universities traditionally give freshman students
the ability to post to usenet; was Robert McElwaine really an actor
for the economic good of his university?

Of course, in a rational economic world the universities would be
reimbursing or even employing those who make such posts, since they're
expending their time by providing a service in increasing the relative
value of the university's own services by polluting the commons -
although they might not be enhancing the university's reputation in
doing so.

Hmmm, brand accounting probably takes care of this thorny problem; in
even slightly damaging the value of the university's external brand,
requiring more effort/expenditure on advertising to counteract, the
poster really is seen to be causing an economic loss while doing
society as a whole a disservice, so it's properly reflected after all
- Bastiat would be pleased, Naomi Klein somewhat less so.

[I would presume jon already had this much figured out before posting
 from ucl rather than cam... a cogent analysis of the effects on
 competition in the marketplace is beyond my limited comprehension of
 economics.]

> ISPs own DNS servers, wich are updated frequently with new entries from the

well, sort of. pull rather than push.

I've gained the impression that DNS as a whole is far less robust than
it used to be; a smaller proportion of working secondary server/valid
secondary entries in root records, so when the one and only (primary)
server for a subdomain goes down everything is unreachable and
effectively toast - as happened to www.researchindex.org last week.

(this is separate from stupidity such as e.g. Microsoft co-locating
all their DNS servers on the same subnet:
http://www.ntk.net/index.cgi?back=2001/now0126.txt&line=39#l
)

has anyone attempted to quantify changes in reliability of a variety
of DNS services in a variety of subdomains - presence of working
secondary/tertiary DNS, uptime, etc. across a large sample? (as
opposed to say presence of valid reverse records for hosts as
discussed in
http://nms.lcs.mit.edu/papers/dns-imw2001.html
, say - my first thought was to wander round www.netcraft.co.uk to see
if they'd already knocked up an ongoing survey for this; my second
thought was that the sheer difficulty of updating records at
e.g. networksolutions could be a perfectly valid reason for invalid
secondary entries!

if a parent domain doesn't have working/valid secondary/tertiary
servers, would you really want a subdomain there, or rely on them to
provide a record for your vanity dns entry?

L.

there's got to be some marginal utility in this.

<[email-masked]>PGP<http://www.ee.surrey.ac.uk/Personal/L.Wood/>