How to check if a domain exists programmatically?

Question

Let's say I have Java or C or C++ or foo language on a computer with a connection to the world wide web and I want to programmatically check if a domain foo.com, or bar.net has been registered, how could I do it without relying on an outside service?

I'm looking for the principle here, code to make a connection is not needed.

I hope you don't consider the DNS and WHOIS to be "outside services", otherwise your task cannot be solved ;-) — DarkDust, Dec 09 '13 at 08:15

score 1 · Accepted Answer · answered Dec 09 '13 at 08:17

1

Your best bet is to ask WHOIS. AFAIK a DNS lookup might not always return a result even though the domain might still be registered.

answered Dec 09 '13 at 08:17

DarkDust

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score 1 · Answer 2 · answered Dec 09 '13 at 08:19

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If you need all information, you'll need to implement the whois protocol. I found this wiki for a list of whois servers (dutch wiki, might be less informative than the english)

answered Dec 09 '13 at 08:19

smeaggie

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That wiki page only lists very few servers. For more complete lists, see the [NirSoft WHOIS list](http://www.nirsoft.net/whois_servers_list.html) or [this SO answer](http://stackoverflow.com/a/18507856/400056). – DarkDust Dec 09 '13 at 08:24

How to check if a domain exists programmatically?

2 Answers2