In the new film “Untraceable,” FBI agents are desperate to track down a maniac who tortures people to death and broadcasts his crimes live over the Internet. To find the villain, the agents use the same Internet tools used by real-world cops and security experts — tools from DNSstuff LLC, a network security firm in Newburyport, Mass.

“The producers contacted us, sent us the script, and asked if we could provide any input,” said DNSstuff’s chief executive, Rich Person.

The company went further: It created Vector Trace, a cool-looking computer forensics tool that appears in the movie and will soon be available to DNSstuff’s customers.

The film, starring Diane Lane, earned over $19 million in its first two weeks. It also provided some welcome publicity for DNSstuff, a five-year old venture that began as a hobby but which raked in about $1.7 million last year, its first year as a money-making business.

Rather than sell network security software, DNSstuff runs a Web site that gives visitors easy access to a variety of standard Internet testing tools.

Anyone with a PC can run a “ping” test, which tells whether a particular network computer is online, or use “traceroute,” which gives a rough idea of where a network computer is located.

DNSstuff combines these standard tests and many others into an easy-to-use Web interface. The service makes it easier to identify network security problems or track down the location of an Internet computer that’s spewing spam or trading in child pornography.

“When DNSstuff produced this for us, it was wonderful,” said Michael Moran, an Irish police officer who investigates child exploitation for the international police agency Interpol in Paris.

“It speeds things up, and it allows me to keep a record of what I’ve done. And it’s reliable. I might be relying on this information later in court, and I…