not exist as top-level domains in the public Domain Name System of the Internet. Most of these networks have long since ceased to exist, and although UUCP still gets significant use in parts of the world where Internet infrastructure has not yet become well established, it subsequently transitioned to using Internet domain names, and pseudo-domains now largely survive as historical relics. One notable exception is the 2007 emergence of SWIFTNet Mail, which uses the swift pseudo-domain. The anonymity network Tor formerly used the top-level pseudo-domain onion for Tor hidden services, which can only be reached with a Tor client because it uses the Tor onion routing protocol to reach the hidden service to protect the anonymity of users. However, the pseudo-domain became officially reserved in October 2015. i2p provides a similar hidden pseudo-domain, .i2p. BT hubs use the top-level pseudo-domain .home for local DNS resolution of routers, modems and gateways. See also List of Internet top-level domains Alternative DNS root Domain hack Domain name registrar Public Suffix List Second-level domain References Further reading Addressing the World: National Identity and Internet Country Code Domains, edited by Erica Schlesinger Wass (Rowman & Littlefield, 2003, ) examines connections between cultures and their ccTLDs. Ruling the Root by Milton Mueller (MIT Press, 2001, ) discusses TLDs and domain name policy more generally. External links IANA TLD List IANA List of TLDs on the DNS Root Zone Articles on CircleID about TLDs TLDs accepted in 2012 Domain Name System Identifiers Internet governance