Dns question

[Andrew Hodgson]

Hi,

1.  DNS should not be used for this purpose, because a domain can be
registered and the NS records can point at stealth nameservers (which do
not exist), or have some other weird DNS configuration.  One thing you
could do, however, is to search the root DNS zones for the domain you
are looking for, and see if the zones for domain.com exist (you will
just get NS records returned, or nothing if the domain doesn't exist),
but I am not sure whether this is 100% fullproof because of the state
some domains are in (i.e, lapsed etc), which may not have records in the
DNS but are not available for active registration either.  

2.  If you do a soa check, do it on the parent domain (i.e, domain.com
instead of www.domain.com).

Thanks.
Andrew.