Download Google DNS table?

[Grant Kiehne]

Is the entire Google DNS table available for download? I would like a
complete listing of domain names and their corresponding ip
addresses. If such a table is not available from Google, how might I
obtain a similar table from an alternate source?

[Paul S. R. Chisholm]

Such a table is not possible to generate.

- Some "wildcard" domains generate unique hostnames. When I visit
www.example.com, it could contain a link to
qerioyqoewryqeri.example.com; when you visit, it could contain a visit
to adsgjfdsagfajdgfjdf.example.com (though both would resolve to the
same address). To put it another way, there is no "complete listing of
domain names."

- Some content delivery networks return different addresses for the
same hostname. www.example.net might resolve to one of hundreds of
different possible IP addresses; the answer I get might depend on
where I am, which of those IP addresses are close to me, which are
lightly or heavily loaded, and which are up and which are down. The
answer you get from another place at another time would likely be
different. To put it another way, for a given name, there is no unique
list of "corresponding IP addresses."

Hope this helps. --PSRC

[jeff...@gmail.com]

Agree with PSRC's assessment. If you look at the way domain name resolution happens; there is no master 'table' -- the entries in the table you seek would be generated on the fly by a somewhat recursive search through various domain name resolution servers.

[Grant Kiehne]

Thanks. Perhaps "table" is the wrong term. As I understand, DNS
servers utilize caching (as described in http://en.wikipedia.org/wiki/Domain_Name_System).
So, does the google DNS server have a cache? And if so, is it
available for public download?

[Paul S. R. Chisholm]

Yes, Google Public DNS has a cache. No, it's not available for
download. I don't know of any DNS service, public or private, that
dumps snapshots its cache and makes them available.

Hope this helps. --PSRC

[Grant Kiehne]

Thanks Paul,

At least for one snapshot in time, I'm interested in obtaining a
reasonably complete listing of all of the IP addresses that have
assigned domain names. Should be simple, right? I've written some
code to recursively query a DNS server (e.g. google's), checking
randomly generated IP's to see if they have domain names. And if the
IP has a domain name, I check to see if I can download a web page from
its associated server. But I'd like the entire list in a file so that
I can make my Internet search experimentation more efficient (a lot of
time is wasted just finding IP's that have domain name entries).

Any idea where I could get such a list? Am I correct that it is
contained within the DNS server cache?

Alternatively, how could I get a list of all of the registered domain
names?

What about a list of all of the IP's that will serve up a web page.
Google must have something akin to this list, right?

On Jan 26, 7:28 am, "Paul S. R. Chisholm" <psrchish...@gmail.com>
wrote:

> Yes, Google Public DNS has a cache. No, it's not available for
> download. I don't know of any DNS service, public or private, that
> dumps snapshots its cache and makes them available.
>
> Hope this helps.  --PSRC
>

> On Wed, Jan 26, 2011 at 5:59 AM, Grant Kiehne <grant.kie...@snet.net> wrote:
> > Thanks.  Perhaps "table" is the wrong term.  As I understand, DNS

> > servers utilize caching (as described inhttp://en.wikipedia.org/wiki/Domain_Name_System).

[Paul S. R. Chisholm]

Nothing on the Internet is simple.

Google Public DNS has a cache, but it's not something that can be
dumped to a file.

I'm afraid your current approach won't work very well either. In
practice, a lot of addresses don't get a satisfactory answer from a
reverse lookup, even addresses that would be returned from a regular
name resolution.

There's no list of registered domain names. What you're asking for is
essentially the content of every authoritative nameserver on the
planet.

Hope this doesn't disappoint too much. --PSRC

[Grant Kiehne]

Thanks Paul,

I will start another thread to provide an outline of my approach. In
summary, I am looking for efficient alternatives to crawling the web
that could be run from a home computer. I figure that using a reverse
DNS lookup would be a reasonably efficient approach. It turns out
that too many entries don't return web pages. For example:

l3-148-104-181-145.l-3com.com
usr022.bb007-01.hg2.im.wakwak.ne.jp
dsl-189-190-219-188-dyn.prod-infinitum.com.mx

Why are there so many DNS entries that appear to be dead ends?
Shouldn't most reverse DNS lookups return actual websites?

Grant

On Jan 28, 8:16 am, "Paul S. R. Chisholm" <psrchish...@gmail.com>
wrote:

> Nothing on the Internet is simple.
>
> Google Public DNS has a cache, but it's not something that can be
> dumped to a file.
>
> I'm afraid your current approach won't work very well either. In
> practice, a lot of addresses don't get a satisfactory answer from a
> reverse lookup, even addresses that would be returned from a regular
> name resolution.
>
> There's no list of registered domain names. What you're asking for is
> essentially the content of every authoritative nameserver on the
> planet.
>
> Hope this doesn't disappoint too much.  --PSRC
>

[songkuk]

Web servers are just a small portion of the all machines connected to
the Internet.
All your examples, I guess, are client machines.

Songkuk