I have a very quick question regarding case sensitive Greek hostnames. For example, if I wished to register the hostname using the Greek letter omega Ω, like so: ΩΩΩΩ.com, it would in actual fact appear as the lower case version: ωωωω.com.

In English of course, this is also true, where E would become e for example. It is not a problem if it is to be read as a language, but if the purpose of this is to use omega as the symbol 'Ω' in the hostname rather than a letter, then it is problematic.

Is there any way around this, in order to maintain the uppercase letter? Are there domain registering sites that offer this type of service?

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    I am fine Paul. How are you? Domain names are not case-sensitive (globally), see here too: faqs.marcaria.com/faq/2758/Greece-GR-Domains/afmfaqs.asp – TheCleaner Sep 18 '13 at 14:23
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    The DNS is case-insensitive. If you register the domain bigspender,com, you may happily use it in literature and links as BigSpender.com, and it will still work. I presume, though don't know for sure, that it's the same with Greek letters. – MadHatter Sep 18 '13 at 14:27
  • Thanks for the quick reply. That's what I was worried about. It's a shame because as I mentioned I wanted to use the Omega letter as a symbol and not as a letter, so by using the lower case version, it is completely different! – Paul Sep 18 '13 at 14:33
  • How can I use the lower case version, but still have it appear as the upper case one in the browser? Is this possible, or does it depend on the server, i.e Windows, Linux etc – Paul Sep 18 '13 at 14:34
  • Symbols are actually disallowed completely. Which is really nice for the person who has ☃.com, and unfortunate for me when I tried to register ⚅.com :( – MikeyB Sep 18 '13 at 14:34

The Internet standards (Request for Comments) for protocols mandate that component hostname labels may contain only the ASCII letters 'a' through 'z' (in a case-insensitive manner), the digits '0' through '9', and the hyphen ('-'). The original specification of hostnames in RFC 952, mandated that labels could not start with a digit or with a hyphen, and must not end with a hyphen. However, a subsequent specification (RFC 1123) permitted hostname labels to start with digits. No other symbols, punctuation characters, or white space are permitted.

Hostname is Case Insensitive.

  • Thanks Abhishek, it makes sense why they did it, it;s a shame though! – Paul Sep 18 '13 at 14:41
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    Useful information, but he's asking about an IDN domain (xn--byaaaa.com). According to this answer, ΩΩΩΩ.com would be permitted. – MikeyB Sep 18 '13 at 14:46

No, and this is by design. Uppercase characters are actually completely disallowed by the new standard and were converted to lowercase by the old.

From the IDN FAQ:

Q: How does IDNA2008 differ from IDNA2003?

A: It disallows about eight thousand characters that used to be valid, including all uppercase characters, full/half-width variants, symbols, and punctuation. It also interprets four characters differently.

Q: Why does IDNA2003 map final sigma (ς) to sigma (σ), map eszett (ß) to "ss", and delete ZWJ/ZWNJ?

A: This decision about the mapping of these characters followed recommendations for case-insensitive matching in the Unicode Standard. These characters are anomalous: the uppercase of ς is Σ, the same as the uppercase of σ. Note that the text "ΒόλοΣ.com", which appears on http://Βόλος.com, illustrates this: the normal case mapping of Σ is to σ. If σ and ς were not treated as case variants in Unicode, there wouldn't be a match between ΒόλοΣ and Βόλος.

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    Paul, if you're happy with this answer, don't forget to accept it by clicking the tick outline next to it. My apologies if you already know this! – MadHatter Sep 18 '13 at 14:41
  • Im a new user so did not know. appreciate the info! – Paul Sep 18 '13 at 14:42
  • would you please check my question? I got an IDN domain, Persian font (like Arabic) with.com extension but can't access to it on most iPhones, not all of them, on the desktop there is no problem, here is my question serverfault.com/questions/962286/… – Cameron A Apr 10 at 6:50

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