The New York City Board of Education is catching some heat over its system-wide internet filtering application after teachers and students complained the program was stymieing legitimate research on the web. The problem appears to stem from the fact that the district implemented the filtering solution, called I-Gear, with one-size-fits-all, company-configured categories.

Responding to criticism, the board of education said schools and teachers can modify the filter, which has kept some students from accessing legitimate research material because the sites happen to include references to sex or violence.

“This is the typical, orderly process of putting new technology in place,” said Chad Vignola, general counsel to the Board of Ed.

Jan Shakofsky, who teaches government and history at Benjamin Cardozo High School in Queens, said students were kept out of the National Rifle Association web site while debating gun control; found the last chapter of John Steinbeck’s “The Grapes of Wrath” blocked because of a scene where a woman lets a starving man drink milk from her breast; and could not research diabetes because one of the disease’s side effects is erectile dysfunction.

But Vignola said the filter known as I-Gear, which is produced by Symantec, “was selected for its flexibility.” For example, in any given school, computers in the library could be programmed so that nothing is filtered out, while computers in individual classrooms or even during certain times of day could be blocked from accessing certain types of material. And while elementary schools might want to block sex education, high schools could allow such material in.

I-Gear is used by about 7 million students in a variety of school districts, from Fairfax County, Va., to Cleveland, as well as in Canada and Scotland, according to Symantec.

New York City has the largest school system in the country with 1 million students in 1,100 schools. The Board of Ed has spent $100 million to connect every one of those schools to the internet. Vignola said that training in the use and modification of I-Gear is ongoing.