What is Punycode converter?
Punycode conversion - is a conversion of domain names in encoding Unicode to encoding in LDH, which is a subset of ASCII characters and includes only letters, numbers and the space character (except the first and last character). Algorithm and transformation rules defined in standard RFC 3492.
What is IDN?
IDN (short from Internationalized Domain Names) - this is domain names that contain international characters, such as сервер.ua
Unicode encoding is used to record domain name since 2003 year, when decision about the need to register domain names using characters from national alphabets was made by ICANN. Internationalized domain names which appeared as a result of this decision, called the IDN-domains (from Internationalized Domain Names). The question compatibility of IDN-domains and exist DNS resolved by the adoption of standards for IDNA (from Internationalized Domain Names), one of which is the standard conversion Punycode .
IDN-domains that have been converting by Punycode converter, easy to distinguish from "normal" domains - a special marker is envisaged by standards - is the prefix «XN -». For example, the domain "BUTTON" after the conversion will look like «XN--H1ADALFG» - exactly such representation is used in the existing DNS.