Automated bulk whois queries?

how/where is it allowed

[limitup]

Say I am developing a cool little utility that needs to do massive numbers of whois queries to determine if certain domains are available, etc. All of the systems I know of all say something to the effect that "high volume automated queries are not allowed" ... so how would I go about doing this?

[Lisa]

Automated queries are not really allowed, You can ask the Registry and they may allow you a whitelisted IP address.

[limitup]

That's what I figured, but I see various domain name related services that do high volume automated queries, and I'm just trying to figure out how they do it. I highly doubt they approach the registrars and ask for permissions (assuming it's not allowed) but you may be right. Anyone else?