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GlossaryDNS and technical

Punycode

Punycode is the encoding that turns internationalized domain names, which contain characters beyond the letters a to z, digits and hyphens, into the plain ASCII form the DNS uses, marked with an xn-- prefix.

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Punycode, explained

Punycode is defined in RFC 3492 (2003), and the IDNA standard adds the xn-- prefix to each encoded label. The German name for Munich, münchen, for example, is stored in the DNS as xn--mnchen-3ya. Registries, registrars and WHOIS records often show the encoded form, while browsers display the native characters, unless a name mixes scripts or looks deceptive, in which case some browsers show the Punycode instead to protect users from look-alike domains.

For a domain investor, Punycode is mostly a due-diligence check. Confirm exactly which characters a name encodes, because characters that look identical in different scripts produce different domains, and look-alike versions of brands are a cybersquatting risk. Check how the name displays in major browsers and email clients before buying. Emoji fall outside the current IDN standard, IDNA2008, so only a few registries accept emoji domains, and support varies by app.

Example. An investor who buys a Spanish word containing the letter ñ will see the name listed in registry records under its xn-- Punycode form.

Sources

  1. RFC Editor — RFC 3492, Punycode (March 2003)
  2. RFC Editor — RFC 5890, IDNA definitions including the xn-- prefix (August 2010)

Education, not financial, legal or tax advice. Domain investing is speculative and most domain names never sell. Read the disclaimer.

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