Four US states are challenging government plans to give control of core internet administration functions to the non-profit group Icann.
The transfer concludes a lengthy process in which Icann (Internet Corporation for Assigned Names and Numbers) has been given more of these tasks.
Arizona, Texas, Oklahoma and Nevada have started lawsuits, saying the decision needs Congressional approval.
The handover is scheduled for today.
Icann keeps an eye on the core addressing system of the internet, known as DNS, via a subsidiary called the Internet Assigned Numbers Authority.
DNS translates the names that humans use to navigate the web into the numbers computers use.
Since the early days of the internet, a division of the US Commerce Department, the National Telecommunications and Information Administration (NTIA), has been involved in approving changes to the core DNS servers.
The NTIA’s involvement in this process is due to come to an end on 30 September.
No formal approval?
Attorneys general in the four states have challenged the transfer, claiming that it cannot go ahead because US politicians have not formally approved it.
In addition, says the lawsuit, the NTIA does not have the power to broker such a deal and it has not consulted the American public about the decision.
The lawsuit also alleges that the transfer does not put in place sufficient protections for the .gov and .mil domains that serve the US government and its military.
The NTIA said it would not comment on the legal challenge.
A judge is due to make a decision on the lawsuit today.
If the judge dismisses it, Icann will assume sole control of DNS.
The plan to stop US involvement in the administration of DNS has won attention from the US Senator Ted Cruz, and Donald Trump’s presidential campaign.
Both claimed the handover would dent the freedom of speech online and give Russia and China more control over the net.
Icann has dismissed these claims, saying: “The US government has no decreased role. Other governments have no increased role.”