What Are International or Internationalized Domain Names?
Internationalized Domain Names, abbreviated IDN, are a 2003 development to the domain name systems. Prior to 2003, only ASCII characters were supported in domain names. The specification released in 2003 (IDNA2003) supported most Unicode characters for domain names. An update in (IDNA2008) approved in 2010 is a revision of the 2003 specification but it is not completely backward compatible.
International Domain Names are currently supported by both browsers and email programs, allowing people to use URLs and links that are fully in their native languages. Because the Unicode is transformed into ASCII internally, there is no change to the system itself, which remains an ASCII-based system. Examples of Unicode letters that became possible with IDNs include German umlauts, and Chinese characters.
IDN Variants
With the new IDNs, there are some specific problems. For example, there are two scripts in Chinese: one traditional and one simplified. If someone wants to register a domain name in one, he or she will be prevented if it is already registered in the other, but there is no way for the domain name registrar to know this until the registration is attempted and the existence of the variant throws up an error message.
IDN Language Tags
It’s important to match the domain name to the chosen language tag and include characters from only one language or language variant in the domain name. These errors also are not detected by the domain search and are only revealed when registration is attempted.
According to DynaDot, VeriSign imposed restrictions on characters that are allowed with the English and German language tags on .com and .net registrations. English domains are, for the moment, limited to the characters a through z, 0 through 9, and the hyphen -. German domains are limited to the characters a through z, 0 through 9, the hyphen -, and three vowels with umlauts—ä, ü, ö. The German letter Eszett or scharfes S—ß is not permitted
IDN and Phishing
The introduction of IDN has led to a type of phishing attack that uses “homograph attacks.” To alert web users of the possibility of a homograph attack, browsers display the Uniform Resource Identifier (URI) using punycode. This warns the user to consider whether the site may be fake.
What Is Punycode?
Punycode is a method of translating international domain names into ASCII characters, so that they only use the character set a through z, 0 through 9, and hyphens, or dashes. When a non-ASCII character is found, it is skipped and another character or characters added to the end of the word using an algorithm called Bootstring. The transformation is such that it can be reversed. Additional characters may also be added to the beginning of the string.
Not all domain name registrars offer a variety of International domain names. However, GoDaddy.com handles a number of domain name services not offered by other providers. Click Here to get GoDaddy International Domain Names.
Sources
dynadot.com
w3.org
Webopedia.com
unicode.org
