The Internet’s key oversight agency is considering a centralized database of trademark holders to cut down on questionable registrations of new Internet addresses.

Officials say the mechanism won’t preclude a new Web site from being created at, say, “www.apple.farm” by someone outside Apple Inc. But it would create hurdles. Backers of the idea say it is needed so trademark holders won’t have to spend thousands of dollars registering domain names defensively, to block someone from registering them and trying to profit — a practice known as “cybersquatting.”