The lowest level of internet governance is that of the Domain Name System (DNS) and of root servers. DNS can be described as a distributed database that stores information about host names and domain names. It provides a physical location (the so-called IP address) for each host name, and lists the mail exchange servers accepting e-mail for each domain, thus assuring that e-mails reach their recipients and users of the internet find the pages they are looking for. Name servers are attributed to a particular top-level domain (TLD), such as .com, .org, .de or .uk.
Root name servers are DNS servers that answer requests for the root name space domain, and redirect these requests for a particular top-level domain to that TLD's name servers. Of 13 worldwide root name servers, only three (in London, Stockholm and Tokyo) are located outside the US.
Since 1998, all root servers have to follow the guidance of ICANN , the Internet Corporation for Assigned Names and Numbers. ICANN is a California non-profit corporation which took over the task of administering names and addresses in the internet. ICANN acts under a contract with the US Department of Commerce. The contract was "sole sourced", which means no-one else was able to submit a bid to perform the task.
Currently, ICANN has responsibility for Internet Protocol [IP] address space allocation, protocol identifier assignment, generic [gTLD] and country code [ccTLD] Top-Level Domain name system management, and root server system management functions. Technically, the US could abuse its oversight of ICANN to exclude any portion of internet users - even whole countries or continents - from access to the internet.