A federal judge blocked the sale of software that lets users flood the Ticketmaster Web site with requests and snap up tickets in bulk, beating people who log in manually to buy tickets.
"We will not allow others to illegally divert tickets away from fans," Ticketmaster Chief Executive Sean Moriarty said in a statement. Ticketmaster is a leading seller of concert and sporting event tickets.
U.S. District Judge Audrey Collins issued the preliminary injunction against RMG Technologies, a privately held Pennsylvania firm that makes the software.
The company argues that the software programs have allowed ticket brokers "to cut to the front of the line and deprive customers of fair access to tickets."
Ticketmaster is owned by IAC, the New York-based Internet conglomerate controlled by media mogul Barry Diller. IAC owns many online businesses including LendingTree, Match.com, Citysearch, Evite and the search engine Ask.com.
RMG sells software to ticket brokers or their suppliers, who resell the tickets at a higher price. Ticketmaster has been battling competitors in the secondary ticketing market, such as StubHub, which is growing rapidly. The success of resellers shows the primary ticket sale price may not have been as high as it could have.