IDNA (Internationalized Domain Names in Applications)

IDNA is the technical framework defining how [[idn|internationalized domain names]] are processed in applications and protocols. The current standard, IDNA 2008 (RFC 5891–5894), specifies how Unicode labels are validated, normalized, and converted to [[punycode|Punycode]] ACE form (xn--). IDNA 2008 tightened rules compared to its predecessor, restricting characters like hyphens and symbols that IDNA 2003 permitted, improving consistency across different languages and scripts.