One of the largest purveyors of pornography on the Web has filed suit to block or overhaul the new dot-xxx suffix on Internet addresses, accusing organizations that assign online addresses of running a monopoly that creates unnecessary costs.

The lawsuit was filed by Luxembourg-based Manwin Licensing International SARL, which owns a network of websites including YouPorn.com and manages Playboy Enterprises Inc.'s brand on the Web, along with adult filmmaker Digital Playground.

The suit alleges the Internet Corporation for Assigned Names & Numbers, or ICANN, used a flawed process when it created dot-xxx, the new porn-focused counterpart to the familiar dot-com and dot-org.

ICANN in March awarded a contract to create the new so-called top-level domain name to a company called ICM Registry LLC, which Manwin and Digital Playground say has abused its position by requiring pornography companies and others to buy up Internet addresses in order to keep squatters from infringing on their trademarks with close equivalents like YouPorn.xxx.

The suit, filed in U.S. District Court for the Central District of California, asks the court to block the new so-called top-level domain name altogether, rebid the contract, or put price controls and service requirements on ICM.

More On This...

"We are certain the claims are baseless and will vigorously defend this matter," ICM Chief Executive Stuart Lawley said. ICANN said its lawyers were reviewing the complaint and had no further comment.

Read more on the ongoing battle over .XXX at The Wall Street Journal.