Once again, Rutgers University is under cyberattack.

Beginning Thursday morning, the university was hit with an "intermittent" distributed denial-of-service attack, overwhelming a server by using multiple computers to make repeated requests.

The attack targeted Sakai, the university's online course-management system where professors post assignments, readings, and other course materials. Previous attacks have crippled the university's email servers, Internet connections, and websites.

Sakai is not used to register for classes or post transcripts, but professors can use it to post grades for their classes.

"Rutgers currently is experiencing system-wide network disruptions that might impact the ability of faculty to turn in their grades and students to complete their assignments," Larry Gaines, Rutgers-Camden's vice chancellor for administration and finance, wrote in an email to faculty and staff.

"Faculty are asked to take this situation into account regarding students who may working to complete their semester assignments," he said.

Rutgers' Office of Information Technology said it "worked with our provider on mitigation and has advised law enforcement of the attack."

The FBI has been investigating the string of DDoS attacks that have continued to plague the university.

In November 2014, an attack took down university networks for several hours. A series of attacks took place March 27 through March 30, and a month later a single attack stretched from April 27 to April 30.

Part of a tuition and fees increase was attributed to efforts to beef up security and infrastructure, and Rutgers hired three cybersecurity firms for up to $3 million.

But as the new year began, another attack took down the university's systems Sept. 28, frustrating students and faculty and leading to more criticism of Rutgers' security efforts.

With the Christmas Eve attack, the university's analog experiment continues.