The fight to reinstate net neutrality rules could return to federal court, if consumer groups and tech companies including Mozilla get their way.

The maker of the Firefox Web browser joined other tech firms and public-interest advocates to fire their latest salvo Friday: They asked a panel of judges to rehear a case that upheld a Federal Communications Commission decision to repeal the government’s open-Internet rules.

In October, the U.S. Court of Appeals for the District of Columbia Circuit determined that the FCC acted lawfully when it voted in 2017 to unwind the protections that had required AT&T, Comcast, Verizon and other telecom giants to treat all Web traffic equally. The telecom agency’s repeal wiped out rules that prohibited broadband providers from blocking websites, throttling consumers’ connections or charging websites for faster delivery of their content or services.

But Mozilla, public-interest groups and trade associations representing Facebook, Google and other tech giants argued in filings that the D.C. Circuit erred in its reasoning. Some said judges misinterpreted decades-old legal precedent, giving the FCC too much leeway without considering the facts, and they asked some or all of the panel to reconsider the decision to uphold the repeal. Mozilla and its allies also faulted the FCC for having “abdicated its ability to regulate the behavior of ISPs for the first time in its history.”

It is ultimately up to the judges whether to grant the request, which some net neutrality advocates concede is far from guaranteed. But net neutrality backers stress the request for a rehearing reflects their unwavering push to restore the widely supported open-Internet protections two years after the FCC decided to dismantle them.

“It’s critically important to the future to the Internet that net neutrality and important FCC oversight, get reinstated,” said Gigi Sohn, a distinguished fellow at the Georgetown Law Institute for Technology Law & Policy. She noted that advocates “should use every means possible, including the rehearing petition,” in their efforts to restore net neutrality.

The FCC on Friday said it remains “pleased” with the court’s initial finding. “We are confident that decision will stand and that we will continue to have a free and open Internet moving forward,” it said in a statement.

The renewed push by net neutrality supporters in federal court marks only the latest legal twist in a policy debate that has consumed Washington for decades. The rules often ebb and flow with the party in the White House, always landing in federal court, leading some activists and corporations on both sides of the fight to call for Congress to resolve the matter once and for all.

The latest saga began after the 2016 election, as control of the FCC shifted to Republicans, led by Chairman Ajit Pai, who believed the open-Internet protections adopted by his Democratic predecessors discouraged telecom companies from improving their networks.

Mozilla and its allies, including public-interests groups and state attorneys general, disputed that. They filed suit against the agency over the repeal, arguing that the FCC had acted capriciously in jettisoning net neutrality protections. In doing so, they pointed to millions of Americans who wrote comments to the agency asking it to preserve the rules on its books.

In October, federal appellate judges sided with the FCC, but with key exceptions: They found that the agency erred in imposing a blanket ban on states enacting their own net neutrality safeguards. Longtime supporters of open-Internet protections saw this as a critical victory, potentially allowing states such as California to proceed with regulating broadband providers in the absence of federal action.

Friday’s filings signal that advocates are not done battling the FCC’s repeal.

One petition, filed by Mozilla and others including the crafts site Etsy and the video-streaming service Vimeo, argued the appeals court erred by overlooking a 2005 case that affirmed the agency’s power to decide how best to regulate telecom giants. They said the FCC’s chief evidence in choosing to subject Internet-service providers to lesser regulation was outdated.

As a result, Mozilla and its peers said, federal court precedent “does not shield forever the agency’s making the same decision on a different record reflecting new or changed technologies.”

Echoing their concerns in their own filing were Public Knowledge and Free Press, two longtime public interest supporters of net neutrality, and the Computer & Communications Industry Association, a Washington lobbying group that counts Amazon, Facebook and Google as members.

“Changes in the way Internet service is delivered and other facts that the panel overlooked justify a different result: reversal of all elements of the FCC’s decision,” said Andrew Jay Schwartzman, senior counselor for the Benton Institute for Broadband & Society, which also signed onto the petition.

Others seeking a rehearing included the National Hispanic Media Coalition and public safety officials in California.