how to check domain is registered

[Roman Mashak]

Hello, All!

Is there any proper protocol or tools to find out if the domain is
registered or available. Actually I'm interested in API functions I can use
in C-program. Are they standard Berkley sockets API functions or some
extensions?

Thanks.

With best regards, Roman Mashak. E-mail: m...@tusur.ru

[Tauno Voipio]

Attempt to resolve it using gethostbyname().

--

Tauno Voipio
tauno voipio (at) iki fi

[Walter Roberson]

In article <StHIe.101$Ob6...@read3.inet.fi>,
Tauno Voipio <tauno....@iki.fi.NOSPAM.invalid> wrote:
>Roman Mashak wrote:
:> Is there any proper protocol or tools to find out if the domain is

:> registered or available. Actually I'm interested in API functions I can use
:> in C-program.

:Attempt to resolve it using gethostbyname().

That doesn't tell you whether a domain is *registered*: at best
it tells you whether a domain has functional DNS entries. However:

a) DNS entries not infrequently have mistakes
b) gethostbyname() is not able to return NS records such as are needed
when the owners have not associated an IP address with the domain name
itself
c) DNS records take time to set up -- time *after* the domain is
registered;
d) DNS records continue to exist until they are removed, which might
not be for some time after the domain registration is lost
(and hence becomes available again)

To answer the OP's question: There are not really any standard protocols
or APIs to determine whether a domain is registered. The closest
to that is the "whois" and "rwhois" protocols, but you have to know
which site to query (which differs for different top-level domains.)

--
Feep if you love VT-52's.

[David Tiktin]

On 05 Aug 2005, robe...@ibd.nrc-cnrc.gc.ca (Walter Roberson) wrote:

> To answer the OP's question: There are not really any standard
> protocols or APIs to determine whether a domain is registered. The
> closest to that is the "whois" and "rwhois" protocols, but you
> have to know which site to query (which differs for different
> top-level domains.)

I don't know of an API either, but there's a pretty complete list of
whois servers at:

http://www.geektools.com/dist/whoislist.gz

If you didn't get a hit from one of these, could you be pretty sure the
domain wasn't registered?

I doesn't seem like it would take more than a few lines of Perl to just
try them all. The list mentioned above seems designed to be parsed,
and I assume that's something like what the geektools whois tool does.

Dave

--
D.a.v.i.d T.i.k.t.i.n
t.i.k.t.i.n [at] a.d.v.a.n.c.e.d.r.e.l.a.y [dot] c.o.m

[James Antill]

On Fri, 05 Aug 2005 19:16:12 +0900, Roman Mashak wrote:

> Hello, All!
>
> Is there any proper protocol or tools to find out if the domain is
> registered or available. Actually I'm interested in API functions I can use
> in C-program. Are they standard Berkley sockets API functions or some
> extensions?

One idea that was proposed was:

http://www.ldap.verisignlabs.com/

...however, I think that's dead now.

--
James Antill -- ja...@and.org
http://www.and.org/vstr/httpd

[Roman Mashak]

Hello, Walter!
You wrote on Fri, 5 Aug 2005 15:22:49 +0000 (UTC):

[skip]
WR> c) DNS records take time to set up -- time *after* the domain is
WR> registered;
WR> d) DNS records continue to exist until they are removed, which might
WR> not be for some time after the domain registration is lost
WR> (and hence becomes available again)
I assume getting SOA entry of domain is the closest way to know if the
specified domain is registered ?

[Walter Roberson]

In article <dd68rj$sqj$1...@relay.tomsk.ru>, Roman Mashak <m...@tusur.ru> wrote:
:Hello, Walter!

:You wrote on Fri, 5 Aug 2005 15:22:49 +0000 (UTC):

:[skip]
: WR> c) DNS records take time to set up -- time *after* the domain is
: WR> registered;
: WR> d) DNS records continue to exist until they are removed, which might
: WR> not be for some time after the domain registration is lost
: WR> (and hence becomes available again)

:I assume getting SOA entry of domain is the closest way to know if the
:specified domain is registered ?

SOA is the closest way within the DNS framework, but as I indicated
before there is a bit of a disconnect between DNS and domain
registration.

The geektools that someone referenced earlier should be able to
get pretty close. I believe that the geektools version of whois
is intended to automate the process.
--
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performance boost for most users by going dual-core [...] because it
is running the adware and spyware that [...] are otherwise slowing
down the single CPU that user has today" -- Herb Sutter