International Domain Names include character symbols unique to the language being used. For example, an "e" with an acute accent (é) is used in French. Each language has an accepted set of characters that are valid within the language set. In addition, each character may have other characters that are considered either close enough in meaning or in visual appearance to be sufficiently similar as to be equal.

When an IDN name is applied for, most registries will reserve the corresponding name(s) that include all of the variants for any of the special characters. Usually, only one of the corresponding name(s) will resolve. Users are encouraged to review the specific rules on variant registrations for each individual registry. To backorder an International Domain Name you must submit it in punycode format, for example, the correct way to backorder "mañana.com" would be to submit "xn--maana-pta.com".