If you want to find out the WHOIS server for a particular TLD then in many cases you can do it with a simple DNS lookup. Just query for an SRV record for the domain _nicname._tcp.tld, like this:
~ jay$ dig +short _nicname._tcp.uk srv 0 0 43 whois.nic.uk.
The answer tells you that the WHOIS server for .uk is on port 43 (as it should be) of the server whois.nic.uk.
Many other TLDs follow this convention including .au .at .dk .fr .de .hu .ie .li .lu .nl .no .re .si .se and .ch. This list has now expanded to include .us and .biz and other registries are actively considering it. Of course for gTLDs with distributed WHOIS services there may be some problems to be overcome.
However, I hope developers pick up on this and start building it into their code. At the moment most developers tend to use a service like whois-servers.net, but this mechanism means they can get the WHOIS server address directly from the registry and so users should get a better experience.
By Jay Daley, Chief Executive of .nz Registry Services
|Cybersquatting||Policy & Regulation|
|DNS Security||Registry Services|
|IP Addressing||White Space|
Minds + Machines