Hello All, Just to refresh my memory, I checked a couple of the IETF standards on this topic.
From the main DNS standard: RFC 1035 Domain Implementation and Specification November 1987 (http://www.ietf.org/rfc/rfc1035.txt )
"The DNS specifications attempt to be as general as possible in the rules for constructing domain names. The idea is that the name of any existing object can be expressed as a domain name with minimal changes. However, when assigning a domain name for an object, the prudent user will select a name which satisfies both the rules of the domain system and any existing rules for the object, whether these rules are published or implied by existing programs. For example, when naming a mail domain, the user should satisfy both the rules of this memo and those in RFC-822. When creating a new host name, the old rules for HOSTS.TXT should be followed. This avoids problems when old software is converted to use domain names. .... Note that while upper and lower case letters are allowed in domain names, no significance is attached to the case. That is, two names with the same spelling but different case are to be treated as if identical." So basically the DNS protocol itself can handle a range of labels, but the applications of the DNS may have restrictions. So the DNS protocol can handle single letter domain names. Prior to the DNS, most computers maintained host tables (ie tables of computer names and their IP addresses) - effectively like a local phone book as many of you might have in your mobile phone. Thr rules for computer names (Host names) are defined in RFC 952 DOD INTERNET HOST TABLE SPECIFICATION October 1985 http://www.ietf.org/rfc/rfc0952.txt "A "name" (Net, Host, Gateway, or Domain name) is a text string up to 24 characters drawn from the alphabet (A-Z), digits (0-9), minus sign (-), and period (.). Note that periods are only allowed when they serve to delimit components of "domain style names". (See RFC-921, "Domain Name System Implementation Schedule", for background). No blank or space characters are permitted as part of a name. No distinction is made between upper and lower case. The first character must be an alpha character. The last character must not be a minus sign or period. A host which serves as a GATEWAY should have "-GATEWAY" or "-GW" as part of its name. Hosts which do not serve as Internet gateways should not use "-GATEWAY" and "-GW" as part of their names. A host which is a TAC should have "-TAC" as the last part of its host name, if it is a DoD host. Single character names or nicknames are not allowed." Note the last sentence above. So the question really comes down to deciding what the impact on existing software would be to allow single letter domain names more broadly. On a related topic I have also heard requests for additional punctuation types such as the "&" sign, or "!" sign in domain names using the ASCII character set. Punctuation characters are used in company names (e.g AT&T, Yahoo!, , and it is now more common for domain names to relate to company names and brand names, than the type of names that were used to label computers in the past. Note these additional characters are excluded from the hostname definition above. As an aside, IDNs do meet the hostname standard, as they are converted from the hostname character set into different characters by end user software. One of the core debates when introducing internationalised domain names, was whether to simple allow UNICODE characters to be represented in the DNS labels directly. Regards, Bruce Tonkin Regards, Bruce Tonkin