Whois.sc is the only such public tool. There are no other similar public tools, let alone free ones...
Yeah, that is Domain Tools *sigh*.
So I guess that me and there aren't any others then?.
Ah well... After about a week of hunting, I give up on this..
DomainTools charges the sort of amounts I could use just to hire some guy to beat a registrar to death with and transfer the domains to me while his fingers are being broken with a ball hammer just before his lifeless corpse is fed to pigs to get rid of the evidence anyway... *sigh*.
I still can't believe on the entire intermawbeotron that there's only one service providing this, and that it likes to rape your credit card more than a Russian porn site.....
Reverse lookups come with their $10/month package. Not exactly a bank breaker if you use the info...
That's the thing, they don't..
I signed up for a month to try it out, and you have to pay an extra fee on top of that..
The fee itself is dependent on how many domains you're trying to reverse look up..
I.e. One guy I was trying to lookup had about 28k domains. The fee was about $2k..
Ok, so after a LOT more searching, I eventually found a site that does exactly what I'm after here! SWEET!.
Downside 1) It's limited to only 12 entries (fair enough considering it's a free service, and how some domainers have 500,000 domains).
Downside 2) Je ne parle pas Espanole... and the site just happens to be in Spanish...
Well, as it turns out, most of this site is useless *sigh*.
And here I was all excited about it..
Nearly all the info on it is wrong as it turns out...
Damn lazy mexicans!..
I assume you're talking about the reverse name lookup tool, where DT searches by email, address or other stuff..
The reason it's so expensive: The only way to get accurate access to that kind of data is to be a registrar, which starts in the $xx,xxx range to be approved by ICANN, and then you have to maintain the code and databases to make it work - you'll notice most of their data (whois history etc) doesn't go before 2001..
The tool really works though and is great for spot-on competitive research...
Yeah, I figured there was a reason for it being so expensive... But there's usually someone out there who has some sort of back door in the system and does it for the love of information that wants to be free, or some other techno hippie claptrap..
If you pay to pull 50 domains then snag the IPs for those 50, chances are you'll have a decent chunk of their hosts. Then just write some quick whois querying software for all domains on those IPs, and compare...