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.
