Checking if a domain name is registered

Question

How would I go about checking if a domain name is registered? I was thinking about checking if it has a corresponding IP but it doesn't seem to work as well as I had hoped. Is there a solution in either PHP or Python that can check?

Answer 1

"Registered" doesn't mean "assigned an IP address". To know whether a domain name is registered, you'll need to do a whois query.

For Python, there's pywhois, but from its web site it seems somewhat immature. Also see this SO question.

For PHP, there's... surprise... phpwhois.

Answer 2

Mike Nott has created a simple PHP class that allows you to query the who.is data for any domain you wish.

Once you call

    $whois = getwhois($sld, $tld);

you then just need to check the contents of $whois to determine whether the domain is currently registered.