Internationalised Domain Names

Domain names are human readable names such as Example.com that people can use to find web sites. When first defined, domain names could contain only the ASCII letters A-Z, numbers 0-9 and the hyphen (-).

These characters are all that English requires to create meaningful names, and served for the early days on the Internet, but since the Internet has gone international, native speakers of other languages that require different characters for intelligibility have become major users of the internet. This restriction on internet domain names has disadvantaged them.

For example, the content of NewZealand.com is pretty obvious to any English speaker, but to Chinese speakers it may be completely unintelligible and they would be more likely to look for the same information on ???.cn

Since changes to the underlying mechanisms to directly support these names could not be achieved quickly a work-around was developed where international characters could be encoded into ASCII and the authors of web browsers adopted this convention. ???.com would be encoded as xn--95q960c09z.com, but as the web browser did all the translation work, the user only needs to type the Chinese characters and never sees the xn-- name.

When used for its intended purpose it was a great boon for non English speaking surfers. Unfortunately criminals quickly saw an opportunity because some non-English languages contain characters that look superficially like English letters, for example the Greek letters Chi and Rho on the Papal arms look like the latin letters X and P.

If you display the domain name xn--pypal-4ve.com it looks remarkably like paypal.com (xn--pypal-4ve.com was used by an Internet security expert to demonstrate the problem and has now been retired). Because of their use in phishing, some browsers refuse to show IDNs and some registries, including the .nz one, have refused to register domain names using this convention. This has frustrated legitimate users of IDNs.


Bruce Clement is a keen domain name investor and commentator. You are free to copy this article under the http://creativecommons.org/licenses/by-nd/3.0/ licence as long as you publish it unchanged and link either to Bruce's blog Domaining .nz at http://domainingnz.blogspot.com/ or to his hub site at http://www.clement.co.nz/

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