UPDATED at 12 pm to include details of a lawsuit filed by coalition of attorneys general.

The FCC’s “Restoring Internet Freedom” order scrapping the agency’s net neutrality rules become official today — triggering calls for protest and legislative action.

The order, which was published this morning in the Federal Register, starts the clock on legal and legislative efforts to overturn it.

Advocacy groups Fight for the Future, Demand Progress and Free Press Action are calling for a day of action on Tuesday, Feb. 27, to demand a final vote on a Congressional Review Act resolution in the Senate, which seeks to overturn the FCC’s repeal of net neutrality rules. A bunch of well-known tech companies, including Reddit, Tumblr, Etsy and Medium are backing this effort, dubbed Operation: #OneMoreVote.

“Now it’s officially go time and the internet is gearing up for a hell of a fight,” said Evan Greer, a campaign director of Fight for the Future.

That’s a sentiment echoed by FCC Commissioner Jessica Rosenworcel, who warned that the agency has awakened a “sleeping giant.”

Mozilla, the not-for-profit organization dedicated to promoting openness, innovation and opportunity on the internet, said it re-filed a lawsuit challenging the FCC’s undoing of its 2015 net neutrality rules that banned blocking, slowing or erecting tolls to access certain web content.

“We won’t waste a minute in our fight to protect net neutrality because it’s our mission to ensure the internet is a global public resource, open and accessible to all,” Mozilla wrote on its blog. “An internet that truly puts people first, where individuals can shape their own experience and are empowered, safe and independent. An internet that truly puts people first, where individuals can shape their own experience and are empowered, safe and independent.”

California is already has taken matters into its own hands. State Attorney General Xavier Becerra joined with 22 other attorneys general in formally commencing a lawsuit against the FCC’s net-neutrality rollback. The coalition, led by New York Attorney General Eric T. Schneiderman, filed a petition today asking for a review in the U.S. Court of Appeals in Washington, D.C.

The attorneys plan to argue that the FCC’s new internet rules violate the Administrative Procedure Act, which prohibits arbitrary and capricious rule-making. They’ll maintain the FCC failed to justify the commission’s departure from its long-standing policy of defending net neutrality, even as it disregarded evidence on industry practices and harm to consumers and businesses.

“An open internet, and the free exchange of ideas it allows, is critical to our democratic process. Repealing net neutrality will allow internet service providers to put corporate profits over consumers by controlling what we see, do, and say online,” Schneiderman said in a statement. “Consumers and businesses in New York and across the country have the right to a free and open internet, and our coalition of Attorneys General won’t stop fighting to protect that right.”

Meanwhile, the California State Senate passed a bill that would preserve net neutrality protections, though legal experts warned such legislation is likely to be overturned in court because the FCC took steps to pre-empt state laws that would seek to regulate broadband service.