WHOIS is a protocol that is widely used for querying databases in order to determine the registrant or assignee of a domain name or IP address (range). In its simplest form, building a small PHP script to query the appropriate WHOIS server and outputting readable information is quite simple, yet complex solutions are usually required to extract full functionality from the WHOIS system.
Below is a very simple script to simply output the registrant of a domain name stored in WHOIS records. There’s minimal security, it doesn’t do much other than check the registrant, it’s poorly coded and it’s not very useful… but it will provide a list of servers and a function or two that may be of use.
Useful Links
>> Delegation details of top-level domains (iana.org)
>> WHOIS on WikiPedia.
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Marty has been involved with online application development for a number of years and has worked with large scale applications both as a coder and project manager. He is currently actively contributing to 7 blogs and maintains over 200 websites. 
Ken has been developing software solutions and managing IT projects for over 20 years. Ken has a computer science degree and, although his focus was previously on Windows based software, his focus is now on blogging and other online projects.
{ 4 comments… read them below or add one }
This code is featured on our University website so it probably explains the spike in visitors.
How do I style this and put in Captcha?
Works great & easy to customize into a real working script. You could release this with Captcha and make it a lot easier for those that don’t know how. Good job Marty.
Simple. Easy. Works. Thank you so, so much.