James Martin/CNET

The Federal Communications Commission's rules for a free and open Internet were published Monday in the Federal Register, putting them one step closer to reality -- and officially subject to lawsuits.

The publication of the 400-page Net neutrality order in the federal government's journal of regulations starts a 60-day clock before it takes effect (on June 12). But it also means companies can officially take the FCC to court over the rules. And they didn't waste any time.

Under the new rules -- approved by the FCC in February and then released to the public in March -- Internet service providers like AT&T, Verizon and Comcast are not allowed to block lawful content, slow down applications or services, or accept fees for favored treatment. The rules essentially provide a framework for all Internet traffic to be treated equally. To do so, the FCC has reclassified broadband in a way that places providers under the same strict regulations that now govern telephone networks.

That reclassification hasn't gone down well with broadband providers, who say it could give the FCC authority to set rates and impose tariffs that could translate into higher fees to consumers, stifle innovation and discourage companies from building new broadband networks and improving existing ones.

USTelecom, a consortium of ISPs, had announced after the new rules were approved that it would file an injunction against them, arguing that they are "arbitrary, capricious and an abuse of discretion," and violate federal law. Just minutes after the rules were published Monday in the Federal Register, USTelecom filed its suit.

If a court decides USTelecom's suit holds water, it could block the rules from taking effect, resulting in a protracted legal mess. Other lawsuits are also expected to be filed in the coming weeks.

The FCC, for its part, is keeping a confident face: "As Chairman Wheeler has said, we are confident the FCC's new Open Internet rules will be upheld by the courts, ensuring enforceable protections for consumers and innovators online," an agency spokeswoman said.