Government officials confirmed on Wednesday what international-student officials at many colleges have long feared: Customs officers at ports of entry into the United States frequently do not consult the federal database that tracks foreign students. College officials are concerned that their hard work to provide data for the system has been wasted and that the system's promise of greater national security has been compromised.

The primary line of customs officers that foreign students encounter at airports, seaports, and border crossings currently does not have direct access to the Student and Exchange Visitor Information System, or Sevis, said Jill Drury, director of the program. Run by the U.S. Department of Homeland Security, Sevis allows officials to scrutinize foreign students and scholars closely in the hope of weeding out potential terrorists.

A secondary line of officers does have access to the database, Ms. Drury said, but only new students and those who prompt suspicion go to that line. A majority of students do not go to the secondary line, she said.

Some college officials say they are exasperated. Their international offices have created new positions, worked thousands of hours, and spent millions of dollars to make sure they meet federal guidelines for Sevis, largely in efforts to provide information to the Sevis database on the hundreds of thousands of foreign students and scholars at American colleges.

"Why in the world are we doing all this work to keep this database up to date if they're not going to use it?" asked Wendy Syer, assistant director for the Center for International Education at the University of Tennessee at Knoxville.

The situation has security implications as well. "This is probably the most scandalous news that anyone could possibly imagine right now, especially with the hearings on Capitol Hill," said J. Greg Leonard, vice president for research and marketing at Newfront Software, which makes software that colleges use to get access to the database. A bipartisan commission has been holding hearings for several weeks, seeking, among other things, to identify government errors that failed to prevent the September 11 attacks.

The Homeland Security Department has not yet reached its goal of giving the primary customs officers access to Sevis, Ms. Drury said. She said she did not know how long that would take.

When foreign students arrive at a U.S. port of entry, Ms. Drury said, they are supposed to present entry documents known as I-20 forms, which colleges issue through Sevis, to the primary customs officer. The officer reviews the I-20 forms, examines supporting documents, and asks questions about the students' reasons for visiting the United States. The officer then decides whether to refer them to the secondary line or let them pass.

But Sevis is supposed to eliminate the possibility that foreign students could use fake I-20 forms to hoodwink customs officers into letting them enter the United States, Mr. Leonard said. Because they lack access to the database, he said, inspectors cannot tell definitively whether the I-20 documents are real or fake. "That was the whole point of Sevis," he said.

Ms. Drury rejected that theory. It is impossible for students to successfully use fake I-20 documents, she said, because the forms' authenticity must be proved before the U.S. Department of State will issue visas to enter the United States.

Nonetheless, Mr. Leonard and Ms. Syer said they have heard of multiple instances in which foreign visitors who have lost their student status -- by taking too few courses, for instance -- have been able to re-enter the United States using their old I-20 forms. If customs officers do not see a reason to check the database and rely on the form alone, Mr. Leonard said, such visa violators will not get caught.