A number of pseudo-top-level domains to be used in naming computers have been defined at various times. These "pseudo-TLDs" include .bitnet, .csnet, .exit, .i2p, .local, .onion, .oz, .freenet and .uucp. Although these pseudo-TLDs look like top-level domains, and serve the same syntactic function in creating names for network endpoints, they have no meaning in the global Domain Name System and are (or were) used only for specialist purposes; typically for addressing machines that were not reachable via the Internet Protocol for use in services such as E-mail and Usenet via UUCP.
Although they have no official status, they are generally regarded as having been unofficially "grandfathered", and are unlikely ever to be allocated as top-level domains. A peculiar case is .root, as it might appear to "exist".
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