The U.S. will go ahead with its plan to hand over oversight of the internet's domain name system functions to a multistakeholder body on Oct. 1, despite fierce opposition from some lawmakers and advocacy groups.

The Internet Corporation for Assigned Names and Numbers operates under contract with the U.S. Department of Commerce the Internet Assigned Numbers Authority (IANA) functions that enable the efficient operation of the internet domain name system (DNS). These include responsibility for the coordination of the DNS root, IP addressing, and other internet protocol resources.

The National Telecommunications and Information Administration (NTIA), an agency located in the Department of Commerce, said in March 2014 that it planned to let its contract with ICANN expire on Sept. 30, 2015, passing the oversight of the functions to a global governance model. NTIA made it clear that it would not accept a plan from internet stakeholders that would replace its role by that of a government-led or intergovernmental organization or would in any way compromise the openness of the internet.

The transfer was delayed to September this year as the internet community needed more time to finalize the plan for the transition. The new stewardship plan submitted by ICANN was approved by NTIA in June.

NTIA Administrator Lawrence E. Strickling said Tuesday that the agency had informed ICANN that “barring any significant impediment,” NTIA intends to allow the IANA functions contract it has with ICANN to expire as of Oct. 1, said Strickling, who is also assistant secretary for communications and information.

Last week, ICANN said Public Technical Identifiers, a nonprofit public benefit corporation, had been incorporated in California, to eventually run the IANA functions under contract from ICAAN, after the transition was complete.

The proposed transfer of control of the IANA functions has been criticized by Republicans in Congress and some conservative groups, who are concerned that the transition will hand over control of the internet to governments, including some that have a reputation for stifling online activity.

Last week, 25 advocacy groups asked Congress to sue to enforce riders it has passed on prohibiting spending of taxpayer money on the IANA transition. On Tuesday, one of the groups, TechFreedom, said the move to go ahead with the transition, which would require the time of NTIA staff and thus appropriated salaries, was a "deliberate affront to Congress."

The courts can still pause the transition in September or unwind it after the contract expires, said Berin Szóka, president of TechFreedom, in a statement. He raised the possibility that private parties could sue if Congress doesn't. The groups, which are opposed to rushing the transition, have said that key issues about the transfer are "not expected to be fully resolved until summer 2017."

NTIA said in an accompanying FAQ on Tuesday that both NTIA and ICANN have formally affirmed that the U.S. government is the administrator of .mil and .gov and any changes made to the top-level domains can only be made with the express written approval of the U.S. government. Senator Ted Cruz, a Republican from Texas, has introduced legislation that stated that the .gov and .mil top-level domains are U.S. property and asked the government to secure in the transition the exclusive ownership, control and use of the domains in perpetuity.

Under the transition proposal presented by ICANN, governments will continue to have an advisory role through the Governmental Advisory Committee (GAC). There is nothing that increases the role of governments over the DNS or ICANN as an organization, and the ICANN bylaws retain the prohibition on government officials serving as voting board members, NTIA said.