【雞】丁酉年辛亥月壬子日 / 十月初六日
Tuesday November 21, 2017

Domain Names

For years there were a lot of problems that existed with multibyte domain names (see below), that were mainly the result of the legacy of the internet infrastructure. End 1990s International Domain Names were proposed however it wasn't until 2009 that the ICANN approved the creation of internationalized country code top-level domains (IDN ccTLDs).

TLD for Asian Countries :
Country
TLD
China (PRC)
.cn
Taiwan (ROC)
.tw
Hong Kong
.hk
Singapor
.sg


Some of the problems that had to be resolved when using non-latin letters are :
  • some characters look the same but have different meaning
  • some languages have optional characters (hebrew) and are they meaningfull for dns ?
  • some scripts see accented letters as one some see it as composition of 2 elements
  • capitalisation

  • problem with encodings (support, conversion)
  • resolving the address must work in 2 ways : www.foo.cn and cn.foo.wwww
  • some punctuation symbols have local alternatives : "." in an IME is often represented as a "。" so should there be support for both or only one of them ?
  • should traditional input be converted to simplified input ? or should it be 2 different domains. but what with simplified characters that represent several traditional characters
The problems are not only specific to DNS-servers. All other machines and programs that have anything to do with name resolving are affected. So webservers, roxy-servers, firewalls and browsers all have to be able to handle it correctly. Also problems can occur for the webbrowsers. See Q269677 for Internet Explorer (this problem is solved already).

Links
CDNC : Chinese Domain Name Consortium
TWNIC : Taiwan Network Information Center
CNNIC : China Internet Network Information Center
MINC : Multilingual Internet Names Consortium.

References
RFC 1034 : Domain names - concepts and facilities
RFC 1035 : Domain names - implementation and specification
RFC 2181 : Clarifications tot the DNS Specification

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